Hi coralie35,
Thank you for posting in the Apple Support Communities. It sounds like when you're attempting to download an app from the App Store, you aren't seeing the option to start the download, correct? This is normally related to restrictions on your Apple ID, or device. Is your Apple ID part of a family sharing plan in which parental controls may be set up? If not, is your Apple ID or device administrated by an employer, or educational institution?
If not, let's try the troubleshooting steps we've linked for you below.
If you can’t download or update apps on your iPhone or other Apple device
You can also check your device settings to ensure you haven't accidentally restricted access by going to Settings > Screen Time > Content & Privacy Restrictions.
Please let us know if you have any additional questions. We're always happy to help.
Cheers!