"The Outlook contacts integration allows every user in the CRM to keep their CRM database up-to-date by syncing their contacts folder from Outlook for Office 365. * The first time the sync happens, all contacts from the selected contact folder are imported, provided the contact has an email address or phone number. * For every subsequent sync, any new contacts being added to the selected contacts folder or any modifications to the existing contacts are synced to the CRM. Please note that this is a one-way sync i.e. Information flow is from Outlook Contacts to the CRM and the sync happens once every 30mins."

https://support.freshsales.io/en/support/solutions/articles/50000000059-how-to-sync-outlook-with-freshsales-to-bring-onboard-office-365-contacts-