Full disclosure here, the links provided are affiliate links so I will get a little commission if you end up buying the software. I use this stuff every day so I would definitely recommend you checking them out.
Transcribing Songs - Transcribe!
I've tried a couple of different pieces of software when transcribing music for students (and YouTube viewers), but I've found Transcribe! by Seventh String to be the best.
As well as standard features like scrolling through the waveform, changing tempo and pitch and looping sections, I particularly like that Transcribe! can work with video formats. I'm often transcribing from videos to be sure of exactly how a song or passage of music is being played.
Creating TABs - Guitar Pro 7.5
I've been using Guitar Pro for over 10 years and I'm currently on their latest version, Guitar Pro 7.5. I use it for all the TAB that I produce for YouTube and Instagram.
This is an essential piece of software for any guitarist, if only for opening up those Guitar Pro files from Ultimate Guitar. I use it to write out all my transcriptions and like that its interface is really intuitive.
It's a great practice tool too. You can loop and change the speed of any number of measures to perfect any part you're having trouble with. There's so much you can do with it. Definitely worth checking out!