I want to know how I can migrate the Exchange Online Mailboxes and it’s contents for all the users on an Office 365 Tenant to another O365 fresh Tenant?
Also, is there any 3rd party tool that i can use to achieve this?
Does Sharegate provide the option of migrating mail boxes too for multiple users?
How can it be done without using any 3rd party tool?
This article should give you what you need
The article references 3rd party migration tools for Office 365 tenant to another tenant migration and Office 365 tenant to tenant migration to be the most comprehensive. Keep in mind that when migrating email, you will have to contact the registrar to change the MX records to point to the new tenant.