Cant we type ".HTML" or ".Html" while saving ?

Answer 1

just same. you can choose the one you went.
but .html is better because some platform are case-sensitive.
there are other possible way .htm

Answer 2

Use lower case extension for wider scope. Above pattern is okay for Windows OS, but Linux based OSes are case-sensitive. These can pose a problem especially while adding them in hyperlinks.

Answer 3

they both are same.

Answer 4

you can, but why?

Answer 5

i wanted to know