How to increase milk supply?

Moms that breast feed, what did you do to build up your supply? I work full time and pump at work and just breast feed at home but I’m noticing I’m not pumping as much as I was I’m having to supplement with formula but the formula we need is literally no where and I want to produce more so I don’t have to rely on formula to feed my baby with the shortage going on. Any advice would be appreciated