Why cant I see the offline basemap on my phone but I can see it in the desktop version?
Which method did you use to get the tile package over to your phone?
I would recommend trying the following...
Prepare basemaps for offline use—Survey123 for ArcGIS | ArcGIS
"A tile package can be attached directly to a survey, so it is available with your survey immediately. To provide your tile package with your survey, add it to the media folder in your survey's content folder before publishing.
Once a survey has been published with an attached tile package, the Survey123 field app will download the .tpk file as part of the survey. The .tpk file is automatically added to the list of basemaps in the map page menu for that survey."
Please provide more details if this does not work for you.
I can see the map in the download map section and I can download it. Once
it finishes I do not see it in the location geopoint selection. It does
work in the desktop version
Retrieving data ...