Sending text messages is not free.
With these chat apps, sending text messages, links, and files is free, and free video chat is also possible.
Facebook:
https://apps.apple.com/ch/app/facebook/id284882215
https://play.google.com/store/apps/details?id=com.facebook.katana&hl=de&pli=1
https://apps.microsoft.com/detail/9wzdncrfj2wl?hl=de-DE&gl=DE
Viber:
https://www.viber.com/de/download/
Whatsapp:
http://www.whatsapp.com
Microsoft Teams gratis für private Nutzung:
https://www.microsoft.com/de-ch/microsoft-teams/teams-free?msockid=260baf52f0016a3e3d54bd34f1b86b46