On your iPhone: open Contacts app → tap a contact → scroll down → Share Contact → AirDrop or Mail to send the .vcf. For all contacts at once, go to icloud.com → Contacts → select all (Cmd+A) → gear icon → Export vCard.

Go to contacts.google.com → select contacts → top-right menu → Export → choose vCard (.vcf) or Google CSV → Export.

Open Outlook → People → Manage → Export contacts → choose All contacts → Export. This downloads a .csv file.

Open the Contacts app → tap the menu (three lines or dots) → Manage contacts or Settings → Export → choose storage location → saves as a .vcf file. On Samsung, go to Contacts → menu → Import or export contacts → Export to phone storage. Then share or email the .vcf file to yourself.