How can I bless a protection charm for m

Tarot doesn't bless charms — the deck is for reading, not consecration. What you're describing belongs to the tradition the charm comes from, and the honest answer is: that tradition has its own way, done by its own people.

If the charm has an origin, go back to it

• Omamori from a Shinto shrine → the charm is already blessed; re-blessing is the priest's at the shrine, not yours at home.
• Catholic medallion, scapular, or medal → any priest can bless it, and many parishes have a blessing Mass or a box at the door. You can also make the sign of the cross over it yourself; that's a private, legitimate version, not a substitute for the sacramental one.
• Jewish items (mezuzah, chai, etc.) → these belong to a koshering or home ritual with its own rules, so check with a rabbi rather than improvising.
• Oil-miracle, pagan, folk, or handmade charm → these are traditionally marked with oil, smoke, salt, moonlight, or a spoken word of your own. There's no single authority to defer to, so a self-chosen ritual is the normal case, not a lesser one.

If it has no origin — you made it or bought it as a plain object
Then a self-blessing is fine, and simple is best. Pick a moment that already means something to you: first light, before you leave the house, or the moment you put it in your pocket. Say out loud what it is for and what it isn't for (not a promise that nothing bad happens), and where you'll carry it. Then use it — a charm that stays in a drawer doesn't do anything, yours or anyone else's. Re-do the words when it wears thin or you change jobs, move, or feel you need to.

If you want something from this deck to sit with it, say the word and I'll pull one card as an anchor for the charm — a card to keep in your pocket alongside it, or a reminder of what you're actually asking protection *for*.