This spread can be used to tell a general fortune, but it is somewhat vague, meaning you will need to follow up with other spreads. It also tends not to go beyond one or two months.
You simply shuffle and cut the cards and then deal them out into seven packs of three cards each. Each small pack has a correspondence.
Pack 1: the querent (usually, but not invariably, the present moment)
Pack 2: the house
Pack 3: external influences
Pack 4: work and money
Pack 5: love life
Pack 6: potential for trouble
Pack 7: something unexpected

If a pack is not clear, shuffle the remaining cards and add two more

If you look up online, you will see that there are many different variations of this spread. This is how it was taught to me, but feel free to adopt the one that you find resonates better with you. I should also point out this is not a spread I use very often with other people, mostly I do it for myself every month or so to see what’s ahead. There are exceptions, or course.

Remember to lay out the cards as in the example and try to come up with your interpretation before reading mine

Example of 21 card spread
Pack 1: 5♦ + 9♠ + 3♣R
Pack 2: 9♣ + 8♣ + 3♦
Pack 3: J♦ + 8♦R + K♠R
Pack 4: 10♥ + 4♠ + 7♣
Pack 5: 5♥ + A♥ + 2♥
Pack 6: 9♦ + 5♣R + 2♣
Pack 7: 10♣ + 2♦ + 10♦

This is an old spread from some year backs. The first pack shows that I was coming out of a bout of depression. The 3♣R breaks negative cycles.
Pack 2 shows a family gathering with the exchange of gifts. A couple of weeks later was my nephew’s first birthday.
Pack 3 shows the arrival of negative communications from the authorities, possibly something to be paid or some money not granted. I hadn’t asked for money though. Around a month later I received communication that I needed to pay for the public broadcast network (even though I never watch it. Yay for unwanted public services)
Pack 4 shows that a long spell of unemployment was coming to an end. I did find a job soon after.
Pack 5 shows harmony in the relationship I’m in and talks about consolidating it. It was around the time we had started considering marriage.
Pack 6 shows that althouth there may be difficulties, all will sort itself out, albeit with a delay
Pack 7 shows the loss of correspondence. I actually ended up losing my phone (which can be signified by the Letter, considering that the Gift card was already in play). A tourist found it and I got it back (remember Pack 6)