My front end is out of alignment how to fixit?

There should be some tie rod ends (like on a car) present under the mower in the front. There is a threaded rod with a locking nut that you turn to adjust the "toe in" adjustment. There should be videos and manuals online to help you with this.

A bigger concern would be why is it out of alignment. Did you hit something hard? Did the locking nut back off? Also, make sure the tires have the right air pressure (PSI) in them. You can find this number on the sidewall of the tire. This may cause the alignment to feel off.