Any self-hosted Strapi project can be hosted on Strapi Cloud. The migration process from self-hosted to Cloud will heavily depend on your Strapi version, database, and asset storage setup. First, you will need to create a Strapi Cloud account and link your GitHub repository with a new Strapi Cloud project.
Support for GitLab / Bitbucket repositories will come in the 2nd half of 2023.
For additional information about migration, we urge you to reach out to our sales team at sales@strapi.io and we will schedule a call with one of our Account Executives / Managers as there are significant differences in terms of pricing and support coverage. In short, Strapi Cloud pricing is usage-based as opposed to our Self-Hosted Enterprise Edition which is user-based.