It seems the Freecodecamp site is not fully optimized for a seamless mobile experience. I am also not able to add/delete a space in the tags. But you can use the site on a laptop/desktop and you will have no complaints.
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.
In my experience when working with FCC on mobile, it is a little finicky, but FCC mobile is totally doable.
For example, my keyboard has “<” and “>” buttons that switches between commonly used symbols and uncommon symbols, however on one of those screens there are extra “<” and “>” buttons for inserting into the IDE.
(this was tested many hours on multiple train rides on a $250 LG android phone purchased in 2018)
(I use Google Chrome as my android web browser)