The covered call is a sale with a ceiling

A covered call is stock you own plus a call you sold against it. The word "covered" describes the call, not you: it means that if the buyer exercises, you have the shares to deliver, so the broker doesn't have to worry about you. It does not mean the shares are protected. They aren't.

One position, three regions

You hold 100 shares bought at $50. You sell a call with a $55 strike, 30 days out, for $0.90, and $90 lands in the account. From here the trade has three regions.

Stock at expiration	Shares	Call	Total
$60	Called away at $55: +$500	Keep $90	+$590, and you're out of the stock
$54	+$400 unrealized	Expires worthless: +$90	+$490, still holding
$50	Flat	+$90	+$90
$40	−$1,000 unrealized	+$90	−$910

At $60 you make $590, which sounds fine until you set it beside the $1,000 the shares alone would have made. The call cost you $410 of upside. At $40 the call handed you $90 against a $1,000 loss. Those two rows are the whole trade: a small cushion on the way down, a hard ceiling on the way up.

Choosing the strike

Everything about a covered call is set by the strike. Closer to the current price, the premium is larger and the ceiling is lower. A $52 call might pay $2.10 but caps your gain at $2 plus the premium. A $60 call might pay $0.25 and barely matters either way. There's no correct choice, only the choice that matches what you think the stock does next and how much you'd mind being out of it.

The premium is often quoted as a yield on the shares: $90 on $5,000 is 1.8% for the month. That's a fair framing as long as you also write down what it cost. The seller who collects 1.8% a month and watches the stock get called away at $55 during a run to $70 has earned 1.8% and given up 30%.

The dividend trap

If the stock pays a dividend and your call is in the money as the ex-dividend date approaches, expect early assignment. A call holder who exercises the day before ex-dividend collects the dividend; when the call's remaining time value is smaller than the dividend, exercising is the rational move, and it'll be made. You lose the shares and the dividend together. Check ex-dates before selling any call that could be in the money by then.

When the stock runs

The stock is at $58 with a week left and your $55 call is worth $3.20. You have three choices. Let it be called away and take the $590. Buy the call back for $3.20, realizing a $230 loss on it, and keep the shares. Or roll: buy it back and sell a later, higher call, say the $60 a month out for $1.50, which costs you $1.70 net today but raises the ceiling. None of these is free. Rolling in particular feels free and isn't. The $230 loss is real and the new call has a ceiling of its own.

Where this belongs

A covered call makes sense on shares you'd hold anyway, at a strike you'd be content to sell at, in a stock you don't expect to jump. It's a way to be paid for placing a limit sell order. It isn't a way to reduce the risk of owning the stock by any meaningful amount, and it's a poor fit for a stock you bought because you think it will double.