Someone was convicted of murder and sentenced to death because a man he only met in a bar pretended his own phone battery had gone flat so the stranger requested if he could use his phone to call an uber taxi to take him home. Note that uber records details of any phone that contact them for service. So when the following morning the driver was found dead and the car missing, the uber-company produced to the police the details of the phone used in calling the cab and that's how the man who gave his phone to that stranger got implicated and eventually got convicted.
Please don't give out your phone to any stranger/person to send a text or do any other thing on it as you run the risk of being implicated in a crime you know nothing about.
It is safer for you to treat everyone as a suspect and advisable to refuse such request.