ok, thanks for help.

so i think i get it now.

use electrum to create 12 words
use electrum to copy a bitcoin address to text file on usb

go to exchange, send bitcoin to that text address, (not to any online type wallet)

then get a 'watch-only' wallet, enter the address and see if bitcoins are there

and never enter the 12 words on any wallet that goes online..

thank you for replies.

so what does it mean "as long as you don't broadcast what it is for"

so are you saying, the seed words created in a coinbase wallet are not secure

and if i use electrum wallet to create the 12 words,
how do i get my funds into the seed words without going online
do i use the coinbase wallet with the electrum seed words?

hi, i'm new, no experience, i'm buying bitcoin on exchanges

i want to cold store without using hardware wallet.
(i've tried keepkey and it is too complicated for me)

my idea is to use, say a coinbase wallet,
keep 12 words safe & not upload backup to cloud
then transfer all my bitcoins from exchanges to wallet
then delete the wallet

then all i need to do is keep my 12 words safe for many years on metal plate
i tested by opening another different wallet  (bitcoin.com),
then, using these words, all my bitcoins appeared
is this safe to do and still work again in say 10 years