There are many ways like blogging , YouTube channel and also thare are so many applications that provides discount on tour by sharing your experiences and activities on their platform.
Well, keep posting your blogs and vlogs on social sites and become popular so that you can get advertisment from different brands and also different travel companies can contact you to work for them. You can also sell your write-ups to travel magazines.
You can be travel blogger or a Instagrammer with huge followers . IN both the cases companies will approach you for endorsements and advertisement . Then you can earn money while you travel. Check the website "BruisedPassport". you will get an idea