Curiosity doesn’t kill the fox. It empowers it!

DO NOT share this phrase with anyone! These words can be used to steal all your accounts. You can't edit/change your seed phrase.

Check each word you have written down on the bip39 words list: https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt
Use the browser's search function (Cmd+F on Mac and Ctrl+F on Windows) to look for each word that you have written down, so you can check the spelling in your backup. If you can't find it, try the closest word.
Make sure the seed phrase is written in the exact same order it was provided, with one space between each word.