My mom has asked me to help her determine how many calories she should be eating per day for weight loss. I know the formula is weight (190) x11 for females but I'm lost after that. Please help. Thanks!
Have her start here, and then go through the TDEE calculator that is linked early on in that article.
Edit to add that while that site is generally for crossfit folks, it still provides you all the typical BMR (base metabolic rate) numbers at the top of the calculator. That's what I would go off of if your Mom isn't real active. If she is active, then suggestions from that TDEE calculator should be close.
It calculates your intake based on how much you want to lose and how long you want it to take. It factors in exercise as well. Logging in food is a little tedious at first, but it gets a lot quicker as you learn the system. It is eye-opening to track your calories every day, and will make you conscious of everything you eat or drink (in a good way).
If she is really motivated to do this, have her start making a log of everything she eats every day. Just doing that often spurs folks to make better dietary choices. If she consults a clinical dietician she should take the logs with her to the appointment. There are some smart phone apps that will track all that info if she is somewhat tech savvy.