Hi Sam

Thanks for posting on the community! I'm happy to help! The best way to add users to your account is by first navigating to your Admin Panel under the Users tile. If the users already have a Lucidchart account select "Add By Email" add their emails to the text box and click "Add to Team". If the users do not have a Lucidchart account select "Add Manually" and follow the same steps as above. If you take a look at this Help Center article it can give you more details on how to do this.

After you have added the users they will need to accept the invitation email sent to their inboxes before being added to the team. If for some reason these users do not receive the invitation email please have them check their spam folder. If they are still unable to find the email please fill out this support form with the emails of the users you are trying to add to the team. 

When users are added to the team you still need to manually share your documents and folders with them. They will not be able to automatically see these charts when they are on your team. If you would like for your team to be able to see and work on any chart you make use our Team Folder feature. To learn more take a look at the Team Folder article in our Help Center.

Finally the users have not been officially added to your team account. This is why they are receiving notifications that they need to upgrade. As for the user that is unable to edit there are a couple of reasons this may be happening:

• Since you are on a higher level account and have shared a document with a lower level account the lower user will automatically be a view-only collaborator since they don’t have access to the paid features you have access to OR
• The user was not given editing permissions. When sharing the document you can change the sharing permissions by clicking the gray drop-down to the right of where you enter the collaborator’s email address. This will define how the collaborator will be able to interact with the document.

Please let me know if you have any additional questions!