fellow members,
As we all know keeping mnemonic phrase in a secure place is the first step of bitcoin journey. But there are few thing that comes in my mind:
->Writing and keeping it with you/your place: What if someone got the access in your absence of theft or any disaster?
-> Obviously keep it online in email of any other way is risking your funds.
What can be the best possible way, My favorite method is to using a metal keycard where I marked the phrase buy again it can be stolen

What your way?
Your mnemonic phrase is usually from 12 words and about, so for me I think the best place to back it up is in your head, maybe after you must as well written it down somewhere you know it can be safe. Keep it safe away from Intruders, let it be one of your topmost secret
So always learn how to memorize it just like your phone number, and let it stick there in your head.
If you save it on your device, your device can easily get stolen or misplaced, or even if you you've written it down, it can as well get missing, so saving it in your head and memorizing it whenever the need arises is the best way to save your mnemonic phrase and to keep your wallet safe.