To carry out the migration of the accounts of another hosting to ours we will need:

Username and password of the old hosting.

Any special information related to hosting (custom DNS, changed records, subdomains, etc.)

To synchronize the email accounts we will need their respective passwords, that will avoid having to change them and will make the synchronization easier.

Username and password of the domain registrar to change DNS and transfer the domain if requested

With this data, the website and the possibility of migration are analyzed.
If you do not have these data, the feasibility of the migration will be analyzed based on the data provided.