Hello Arlindo300
We understand that you're unable to share a list, in the Reminders app. Be sure you're completing the following steps:
You can share a list and collaborate with people who use iCloud. People who accept the invitation can add and edit items, mark items as completed, and all the collaborators can see everyone’s changes. Everyone you collaborate with must be signed in with their Apple ID and have Reminders turned on in iCloud settings.
1. While viewing a list, tap
.
2. To change the access and permissions, tap the share options below Collaboration. You can set either of the following:
Allow access to only people you invite.
Allow others to invite.
3. Choose how to send your invitation (for example, using Messages or Mail).
If you send the invitation in Messages, you get activity updates in the Messages conversation when someone makes changes in the shared note. Tap the updates to go to the shared note.
Click here for more details: Share lists and collaborate in Reminders on iPhone
If you continue to experience the same issue, we'd like to provide you with a few steps that can help:
- Restart your iPhone
- Update your iPhone (Secure your data with a backup)
We hope this helps.
Take care!