There are multiple ways to capture points, lines, and areas in Survey123. Capture points by tapping the map, using your current location, or by searching for a location by name or coordinates. Draw lines and areas as a sketch, or vertex by vertex.
Geosearch and geocode
Geopoint questions include geosearch functionality, allowing you to search for an address or point of interest and have the map zoom to and place the geopoint marker at this location. To search, tap the location panel in the survey to open the full screen map. Type the address or location in the text box at the top of the screen and select the correct result from the autocomplete results. The map zooms to the location.
By default, geosearch returns results from the entire world, using the ArcGIS World Geocoding Service. The survey author can optionally configure a custom locator. To choose a different locator, tap the globe option to the left of the search box. This opens a dialog box allowing you to change the search mode between Search everywhere and Search within the visible map extents, accept Map coordinate input only, or to choose a different locator. If you're not signed in, you only have access to the ArcGIS World Geocoding Service.
Geocoding (return coordinates from a supplied street address) can be used to capture geometry without the use of a map question. A text question with the geocode appearance allows entry of a street address into a text question and will generate coordinates for the survey record.
Reverse geocoding (return street address or other location description from selected geographic coordinates) can also be done in the full screen map to display the details of the geopoint. To do this, either long press the location on the map or long press the coordinate display at the bottom of the screen. The location appears above the coordinate display. The reverse geocoded location won't be submitted with the survey response.
Capture points
You can capture points by panning the map so that it is centered at the location you choose, by tapping the Location button 
or by searching for a location or map coordinate.
While panning the map, or when you tap the capture at location button, the coordinates of the current location are shown at the bottom of the map window. Tap these coordinates to add them to the search bar so that you can refine the values. To return to searching by location, tap the cancel button in the search bar.
When typing a map coordinate directly in the search box, enter comma-separated decimal coordinates. For example, the following coordinates will center the map at the Eiffel Tower in Paris: 48.858328, 2.294514.
Capture lines and areas
Lines and areas have two capture methods, sketch and vertex. The survey author defines which method is used by a survey.
Sketch
The sketch method captures the
geometry in a single motion, with the capture completing once the
user has stopped drawing this single line. To begin capturing
sketch geometry, tap the Sketch button 
and begin drawing the shape on the map. When you finish sketching the geometry, stop interacting with the map. The
geometry is then complete, with the geoshape connecting the
beginning and end of the shape if necessary. The length of a geotrace, or the area and perimeter of a geoshape, is displayed
below the map.
The sketch method also provides a smart shape
option, which attempts to simplify the sketched geometry into
an ellipse, rectangle, or triangle. To use smart sketching, tap
the Smart Shapes button 
and begin drawing the shape on the map. If the sketch is recognizable
as an ellipse, rectangle, or triangle, the app automatically
converts it. If the sketch doesn't resemble one of these shapes, no
geometry is drawn.
When you finish drawing the geometry, either tap the Confirm button to accept this geometry and go back to your survey, or tap one of the drawing buttons to erase it and draw another geometry.
Vertex
The vertex method allows more precise
geometric capture of a line or shape by placing vertices
that connect together. To begin capturing vertex geometry, tap
the Vertex button 
and tap the map to
place the first vertex. You can place more vertices by tapping the map again or tapping the Capture Vertex at Location button 
to
place a vertex at the location of your device.
To move the map instead
of placing vertices, tap the Pan and Zoom button 
to change map
interactions to navigation mode. You can then capture a vertex at
the map's central point with the Capture Vertex at Crosshair button 
.
If you place a vertex at the wrong position, tap
the Undo button 
in the lower right to remove the last vertex placed,
drag the point to move it to a new location, or drag the point to the Delete button that appears at the top of the map window. When you finish, you can tap the Confirm button to accept this geometry and
go back to your survey.
If vertex streaming is enabled by the survey author, the Follow button 
will display. Tap this button to begin capture. Line or area vertices are captured at a nominated minimum distance interval as you move around. The default minimum distance interval is 10 meters, but this can be changed by the survey author. For more information, see Capture methods.