[AC Question]

i want to add a .pdf to the text

[ManiacJoe]

Which phone?
Which version of android?
Which carrier?
Which texting app?

In most apps, after you start the message, there is a "+" button to tap to add a file.
Adding the file converts the SMS message to an MMS message.
Most carriers have size limits on the size of the file, and the limit is usually quite small, like 600KB to 1 MB.
MMS message use a mobile data connection, not wifi.