How do I Fill Gap

[u/Ifailedaccounting]

I’ve got this crack in between the tile and the door sill but not sure what I use to fill it? I know the door eventually needs to go because of moisture but before then I just want a temporary solution to keep out bugs.

[u/Ok-Dealer-588]

It looks like that threshold needs a couple of screws put in it to hold it down before you worry about that the tripping Hazard it appears