How to spell correctly?
On the internet write with and without an article.
Open in new tab
Open in a new tab
Examples: Open a URL in a new tab
How to open link in new tab on html
Sometimes in titles, and other contexts like in a list of instructions, articles that would usually be there are omitted. This is probably to save space on the page and to save time for the reader- when you’re reading instructions you want to be able to follow the steps quickly, so omitting words like articles that don’t really affect the meaning of the sentence will not affect the reader’s understanding.
TL;DR: including the article is correct, but omitting articles in certain contexts is ok.
That being said, the last sentence you have there is not grammatical. You don’t say “on html”; you say “with html”.