The app I absolutely use on a daily basis is the Ultimate Guitar Tab Pro app. It makes my life as a musician 100x easier. Its basically an app where you search a song and it shows you how to play it through guitar and bass tabs. Tabs are a simplified way to read how to play the guitar and bass. The layout is a basic line with 4 to 8 or however many strings the guitar. It will tell you the tuning and it will have numbers from 0-24. Those represent the frets (0 being open strum). In the song you search you can switch guitars if there’s more than one guitar in the band, bass, vocals, drums, piano, and effects. There is the ability to slow the tempo down if there are sections that are too fast for that person at the time. Sections can be looped too. The app plays through the song and is sounds extremely accurate to the actual song. I favorite the songs I’ve learned, liked, and need to learn because when you’re underground with no service or WiFi, there is still access to the songs you favorited. Personally I have learned a ton from this app. Back before I downloaded it, I used to go to their website and screenshot every section of the song and figure out on my own by playing what I see to see which part is which. Now with the app I’m never lost.