Do you mean find the last word? There are webpages you can download and use offline. I have spreadsheet and terminal command that will do it for coin flips. Some hardware wallets will do it. You could also guess. For a 12 word seed phrase you have a 1/16 chance of guessing a working 12th word.

Posted to your thread on X but you can do it on the coldcard https://haven.sdbitcoiners.com/679f7e9c3c534fa2f697ba4d3d075014f244ca01b414565ba20fbdd025e323a3.jpg

I think there is a tab to calculate the last word but didn't check in for a while https://bitcoiner.guide/seed/ Be careful and only use the page offline with real seed