Yes, minors can
apply for IPOs
through Zerodha using
UPI if their bank supports it.
Once allotted, the shares can also be sold from the minor account.
If UPI is not enabled for minor accounts, you can use the net banking ASBA route and provide the minor's demat account information to apply (subject to your bank's policies on minors applying for IPOs). If the minor uses someone else's bank or demat account, the RTA may decline the application. Minors can also apply for IPO in the HNI category.
You can enable Kite access for minors if it's not already enabled. To learn more see Minor account FAQs.