Respuesta :

It depends but here's my list:
For thumbnails - you can use a combination or one - Paint, Adobe Photoshop, Pixlr...
For video editing - Adobe Premiere, Sony Vegas Pro, Cinelera...
I listed a few, what matters is if you want to pay, or if you want free ones.

For thumbnails I use ibs paint x

For videos on pc I use screencast screen recorder (for screen recording)

For videos on devices I use KineMaster and sometimes Video Star

(My channel is Sassy Sparkle, the one with about 41-50 subscribers)