Podcasts are just a fancy term for what essentially just boils down to "recording yourself talking," whether its alone or with others/guests. If you want your podcast on a service like Spotify you have to put in some work and money, but otherwise it really is just as simple as having a microphone and any sound recording software. Audacity is free and can do the job perfectly fine. Make sure while you're talking that your volume is loud while not clipping, then just upload your recording wherever you want. Staple it onto some still images and put it on Youtube, or check out some of the options for podcast hosting, this link shows you a bunch:
https://www.adamenfroy.com/podcast-hosting