I use an import activity + automation studio to import the data from a salesforce report to marketing cloud daily at a given time in the morning so after importing it an email can be sent to those people inside my DE. The problem is that the email field from the salesforce report is imported as TEXT in the data extension and, because is a DE generated from a SF import, it wont let me edit the field type. Any help would be appreciated to resolve this issue.
Make sure your target data extension has the email field as an
email address type. Then your automation should convert that text from the import into the correct format.
This is an issue the old salesforce import activities always had. The fields are not always interpreted correctly when you select them. Email got bungled every time.
You have to check very carefully if the data type is correct. If not, you have to change it in the import configuration window.
Unfortunately you can't (or couldn't last time I used them) change the field type afterwards. You have to delete the email field in the data extension first. Then you can add it again with the correct format.
It's best to check the other fields as well to find other potential issues while you are at it.