Potty training. I don't get it?

Alright, so my dog is crate trained. She never goes potty in the crate. I've heard crate training is key to potty training, but now that she's perfectly crate trained, I'm not really understanding how that translates to being trained in the rest of the house. She still will pee or poo if I let her out in the house. What is my next step? I take her outside and reward her when she potties outside, but she still won't let me know she needs to go out, and she's a quick one. She squats and pees and then it's too late. I'm feeling really discouraged that I can only really have her either in the crate or outside. She's a frenchie and the summertime is coming. She can't be outside all day. She doesn't even really like being outside by herself, and I can't be out there all day. I hate leaving her in the crate when I'm home, it just doesn't make sense. I'd so appreciate some clarification. I'm definitely missing a step here. Help :(

Thank you so much.