When we talk about migration of Exchange mailboxes to Office 365, then there are multiple methods like cutover, staged, and hybrid migration. If you have used any of these methods, then you must be aware that all these methods require creating a batch of the mailboxes in a CSV file, configuring the Exchange settings for a smooth migration, and running the batch. This process takes time, and the administrator needs to monitor the migration process throughout the time continuously.
Are you looking for a replacement for Outlook Public Folders? The Office 365 groups gives a rational place to multiple Office 365 accounts with whom you want to communicate, share, or send the information routinely. It amplifies the percent of collaboration between the users, teams, clients etc. If you are working on a special project where you need to share the documents, spreadsheets, project plans, etc. with your team member, then you should create the Office 365 groups.
Before creating the office 365 group, you need to recognize the need of your organization as there is no Office 365 group that fits for all needs. Different teams look for different levels of collaboration, so you need to create the groups for the different applications also.
When you want to migrate public folders from Exchange to Office 365, then there are no direct methods, but you can perform the migration using Exchange Management Shell.