The geographic data (latitude, longitude) isn't saved in content I have installed the Geofield module, created a new content type, and added a geofield field.
When I start to add nodes with latitude and longitude, those values aren't saved. Editing again the same node doesn't show any value for latitude and longitude.
What I'm trying to do is to install the Leaflet module, so I need to save the values first with the Geofield module.
Geofield module doesn't work without the GeoPHP library. You need to download both the module and the library and place them in the correct locations in order for the module to work.
When using Composer to install Drupal and modules the library is automatically downloaded to the correct place.
If you're not using Composer you can do that process manually. You probably already downloaded and installed the module Geofield in the common location /web/modules/contrib.
Now you have to download the GeoPHP library, you probably want the latest stable version, from the page noted on the Geofield documentation: https://github.com/phayes/geoPHP
The library is compressed, so you need to extract the archive file to get the folder with the library files. Then place that folder in your Drupal installation, usually in /vendor folder that is within Drupal root folder, so you end up with something like /vendor/geophp/ (I haven't checked the exact path and name).
Check the Status Report that the library is available and read properly by Drupal. Sometimes you need to adjust the library file permissions or ownership so Drupal can use it but I don't expect problems in cPanel.
Not using a Composer makes maintaining your site more difficult. You'll have to do updates manually and check for all dependencies yourself.
If you can invest a bit of time and use your computer for development you should install Composer and use it to build your Drupal site. Then just upload the resulting files to cPanel to host your site, but always keep a local copy with Composer to do the updates and maintenance.