It really depends on the area.

Obviously game shops and hobby shops often have groups, since they also tend to carry games.

Libraries sometimes have D&D or similar games run on a semi-regular basis.

There are sites like Meetup that may also have groups in your area. There are dedicated sites for roleplaying games in particular, but the only one I've found particularly helpful is the D&D Adventurer's League one just because others tend not to be particularly reliable: http://dndadventurersleague.org/find-a-game/

Adventurer's League is also pretty good about generally keeping things newbie-friendly.

However, another thing that a lot of people do is run games online through software like Fantasy Grounds, Roll20, or even just Discord. I'm not familiar with D&D being run this way, but I've matched up with other games this way (either through Discord servers dedicated to particular games or through Roll20's Looking For Group feature). I'm not a giant fan of Roll20, but if you haven't been able to play and want to find a newbie-friendly game it works decently.