Migrating to Office 365 requires planning and a pretty good knowledge of the environment you are going to migrate to. This will help you decide on the type of migration you need, for example, cut-over versus staged or hybrid migration. To help with this, you can use the Exchange Server Deployment Assistant at https://technet.microsoft.com/en-us/office/dn756393.aspx.
The aforementioned migration choices can be explained as follows:
- Cut-over: This is a one shot and you're done technique regarding moving all your data to Office 365. I would suggest you use the Assistant because there are limits as to how many mailboxes can be moved.
- Staged: This is a batch version of cut-over, where you move all your data in stages. This is a more ...
