I want to share some of the common online resources that you can use to learn guitar. The internet has tons of useful and free materials, TABs, chord sheets, tuner apps, and more, which are great for anyone who plays guitar.
This is easily the number 1 most popular site for finding guitar tabs and chords for almost any song you can think of. Users upload their own tabs and anyone can rate them based on how accurate they are. There are also Pro tabs (which aren't free), I haven't found it necessary to pay for Pro tabs, but they are usually spot on. There are often many versions of the same songs, some simplified, some using capo, etc. There are many other similar sites, but this one has the biggest library. Check out the site and search for your favorite songs, and you will be almost guaranteed to find them.
This is a free tuning app which is very easy to use. Simply play the guitar strings, one at a time and the phone or tablet will pick up the sound, and beep when the string is in tune. The app also has settings for ukulele, bass and other string instruments.
YouTube needs no introduction, but it is a great resource for guitar lessons. From learning full songs, to strumming patterns, to iconic riffs and more, you can find a lot of useful lessons from teachers and famous players. There are lots of channels dedicated to learning songs, and even some advanced lessons taught by players such as Eric Johnson, Paul Gilbert, Brad Paisley, and many more. You can also find backing tracks to practice your soloing. Simply search something like "Smoke on the Water Guitar Lesson" or "Hybrid Picking Guitar Lesson" and you are sure to find useful videos.
This is another site, like Ultimate Guitar. The one main difference is that you can often listen to the song as the tab highlights and scrolls along. This can be very useful if you don't know the rhythm of the strumming/riff, or if there are more notes than you anticipated. Songsterr has a good sized library and you can likely find most songs you are looking for on there. If you are someone who learns by listening, then you will find this superior to Ultimate Guitar. They might be lacking in some songs that are deep cuts, but I think this is overall the best tab website for beginners and beyond.
For anyone who needs to write actual music notation or tabs, this free software is great and easy to use. I realize a lot of beginners won't be notating full songs, but you can create your own tabs or lead sheets and print them easily. This might be necessary if there are no sufficient tabs online, or if you are creating your own songs. Teachers will find this software very useful for creating lesson materials. This can also be used for any instrument, not just guitar.
These free resources should help get you started in your guitar playing journey. Even as an experienced player, I use some of these resources weekly, especially with my students. And of course, you can take virtual or in-person lessons to take it to the next level!