The domain name was previously managed under my web developer but now I want to manage the domain myself. How to change or transfer the domain ownership?

If your web developer managed the domain with IP ServerOne, you may ask them to initiate the domain name ownership transfer via IP ServerOne customer portal.

Here is the guide to transferring ownership of the domain via the customer portal: How to Initiate Domain Ownership Transfer

However, if your web developer manages the domain name under a different domain provider, you may submit a request to transfer the domain name to IP ServerOne at cs@ipserverone.com and provide the authorization code (EPP) for us to initiate the domain name transfer. You may refer this guide to transfer in the domain to IP ServerOne: How to Transfer Domain.