If you are using a mobile device, the default keyboard does not always play well with the freeCodeCamp editor. I recommend you read the article on using a mobile device to view some tips - most importantly, check out the coding keyboards listed as they interface with the editor well.
<h1> This is a starting tag and </h1>This is a ending tag.
You should add the word “world” inside the tag <h1>.Just give a space after Hello and type world .
It is great that you solved the challenge, but instead of posting your full working solution, it is best to stay focused on answering the original poster’s question(s) and help guide them with hints and suggestions to solve their own issues with the challenge.