https://kb.synology.com/en-global/DSM/tutorial/Quick_Start_External_Access

https://kb.synology.com/en-us/DSM/help/WebStation/application_webserv_desc?version=7

Standard e-mail is Synology Mail Server app.

https://kb.synology.com/en-global/DSM/help/MailServer/mailserver_desc?version=7

Webmail is provided by Mail Station app (RoundCube).

Advanced e-mail is available with Synology MailPlus app. 5 users are free and more are at extra cost.

Mobile apps are available.

Outlook uses IMAP.

https://www.synology.com/en-global/products/MailPlus_License

https://kb.synology.com/en-global/DSM/tutorial/Quick_Start_MailPlus_admin

https://kb.synology.com/en-global/DSM/tutorial/Quick_Start_MailPlus_users

https://kb.synology.com/en-us/DSM/tutorial/How_to_access_files_on_Synology_NAS_via_FTP

https://kb.synology.com/en-global/DSM/help/DSM/AdminCenter/file_ftp_setting?version=7

https://kb.synology.com/en-global/DSM/help/DSM/AdminCenter/file_ftp_sftp?version=7