This is a list of resources and challenges to learn and practice web exploitation and bug bounty for CTF's.
Hacker101 Videos
CTF101
Wireshark Tutorial
TryHackMe How the Web works
TryHackMe WebHacking
Tools For BugBounty
OwaspTop10
BurpSuite Tutorial
PayloadAllThings
Some list of writeups to help you better understand.
PicoCTF -2019 Web Exploitation
Deskel's CTFLearn write-up
Codefest CTF 2018: Writeups
GLUG-CTF web writeup
PicoCTF
CTFlearn
Ringzer0ctf
Practice CTF list
Owasp JuiceShop
PortSwigger WebAcademy