Edit texture command

yes, it is possible. Or you just use the creative mode, there is a tool for that

Quote from Ash_lee

So I would like to know if it is possible to change a regular texture to a glass texture with the edit texture command. If not, I suggest adding one

Yes, as Avanar mentioned above or with F8.

It is also possible to change the shape to glass later, although this shape is not available among the glass shapes. Works with "edit shape...form".

Same works with F8 but some forms as blocks are not changed correctly, I have already reported this.