Inmates are not permitted access to text messaging through any authorized channel, so if you are receiving texts from your friend inside, it is almost certainly coming from a contraband smartphone that was smuggled into the facility.
The contraband phone problem is significant and widespread across correctional facilities nationwide. Smartphones get smuggled in through visits, through corrupt staff, through food deliveries, and through creative methods that facilities work constantly to shut down. Once inside, they circulate and get used for exactly this kind of unauthorized communication.
Here is what you need to understand about the risk on her end. Getting caught with a contraband phone carries serious consequences. Additional criminal charges, extended sentences, SHU placement, loss of privileges, and a black mark on the institutional record that affects everything from parole consideration to housing classification. Every person who has ever had a contraband phone inside has believed they were being careful enough. Most get caught eventually, either through their own carelessness or through another inmate informing on them.
When the phone is confiscated, which it will be, the facility goes through every number in the call and text history. Your number will be on that list. That means you could be blocked from the approved call list and potentially flagged in the system as someone connected to contraband activity.
On the money question, verify her identity through official channels before sending anything. Call the facility, confirm she is housed there, and send money through the facility's approved deposit system rather than through any method she suggests via text. Protecting yourself while this situation plays out is important.
Encourage her to stop using the phone. The risk is not worth it.