Hello @Gavin Bilington
Welcome to the Atlassian community.
Referring to @Fabio Racobaldo _Catworkx_ 's reply, at what point in his guidance are you not able to follow the steps?
Are the users you want to add using email address for account that they set up, or email addresses provided to them by your company or another company?
Ultimately the person who is the Organization Administrator for your Atlassian Cloud Organization should be able to grant the users access to the Jira instance by navigating to https://admin.atlassian.com.
Once there that person should find options for Directory > Users. From there they should be able to see if the user accounts' access to your instance are active, suspended, or not present. If they are suspended then they can be restored to re-grant them access. If they are not present then they need to be re-Invited.
The tags on your post indicate you are using a Free subscription. If that is accurate be aware that there is a limit of 10 active users for such subscriptions. If you go over that limit you will be automatically shifted to a subscription for which you will have to pay, unless you reduce your user count and pro-actively downgrade back to the Free subscription.
You must be a registered user to add a comment. If you've already registered, sign in. Otherwise, register and sign in.