You received below mail with invitation from Doctor/Clinic to GlucoContro Online:
If you want to accept the invitation, make sure you already have an GlucoContro Online account.
If you do not have an account at GlucoContro Online, follow this guide on how to create one:
How to register in GlucoContro Online? – GlucoContro.online Help Center
After successfull log in, you should notice a profile icon with a red dot on the left side of the screen. Click on it.
The panel should expand and show the invitation from the doctor / clinic with the option to accept or decline. If you are sure that it is the correct doctor / clinic click "Accept".
You will be asked to share the data with the doctor / clinic.
Click "Yes, share data".