This is how I make lots of face masks fast. using a serger & straight stitch sewing machine. A zigzag could be substituted for the serging. I've made over 1500 in 4 months. I start with about 3 yards & rip into 13" X 3 yards. I serge both long edges. (If your fabric has nice selvedges, you can skip serging the selvedge edge.) I then rotary cut the strips into 9" segments. With the serged edges at top & bottom, fold the top down about an inch & the bottom up to almost the top fold & press. Gently bend both ends of a 6" piece of wire & tuck into the top fold. Sew around wire. to keep in position.
Serge both edges. Don't you love my variegated thread?-special buy from a thrift store.
Make 2 pleats, tucking the ends of an 8" piece of 1/4" elastic about 1/2" into the folds.
Sew down pleats, back tacking over elastic.
If you're going to put them in a container for people to take, place each mask in an individual plastic bag to avoid possible cross contamination of the masks from asymptomatic people. I've been leaving them in a bag hanging under my mailbox for local people to take. The ones that I have given to a local hospital (150, so far) have not been bagged.