Domain Name:

A domain name is your website name. A domain name is the address where Internet users can access your website. A domain name is used for finding and identifying computers on the Internet. Computers use IP addresses, which are a series of number. However, it is difficult for humans to remember strings of numbers. Because of this, domain names were developed and used to identify entities on the Internet rather than using IP addresses.

Name of some companies which provide free domain name:
freenom.com
dot.tk
biz.nf
biz.ly
www.ionos.com/domains/free-domain-name

Website Hosting:

As the name suggests, free website hosting is a free non-paid web hosting service. There are many web hosts who provide subdomains to anyone who want to make website.

Name of some companies which provide free web hosting:
Firebase
Back4App
AWS
Kinvey
Backendless
Heroku