Hi
If in zoho you are in IMAP, see that guide; https://learn.microsoft.com/en-us/exchange/mailbox-migration/migrating-imap-mailboxes/migrating-imap-mailboxes
If in poo3, see that guide; https://community.spiceworks.com/t/migrate-pop3-email-to-office-365-step-by-step-in-easy-ways/1013780
I would ask how many users you migrate, as if a small number it can be easier to just configure the tenant and add an email account inside each computer to have the new emails, and the copy the old email after hand.