Lands or buildings in Skyrim are not necessary, but a fun addition to the game. You can build anything from a kitchen to a trophy room on the land you purchased. There are three available plots of land that can be purchased in Skyrim: Hjaalmarch, Falkreath Hold, and The Pale. Lots become available only after you have purchased and installed the additional "Hearthfire" mod.
Steps
Part 1 of 2: Launch the Game

Step 1. Install the Hearthfire add-on to the classic Skyrim
If at the moment, of course, you have not yet installed the game, then you must install it. If you have the game installed, follow the next step.

Step 2. Launch the game

Step 3. Once you have launched the game, proceed to the city
It doesn't matter which city you go to.
Part 2 of 2: Get the Earth

Step 1. Wait for the messenger to approach you
The messenger must inform you that he has a letter for you. This will be a letter in which it will be written about the lands that can be purchased.
The lands available are: Hjaalmarch in Morthal, Falkreath Hold in Falkreath, and The Pale in Dawnstar

Step 2. Go to Morthal, Falkreath, or Dawnstar
Choose any of these three cities; all three will have their respective Jarl and quests (tasks) that you must complete.

Step 3. Enter in the city of your choice into the Jarl's hall
As soon as you get inside, talk to the Jarl, and you will be given a task.
In Skyrim, you cannot buy a house / land until the Jarl recognizes you

Step 4. Complete the tasks that the Jarl gives you
As soon as you finish with the tasks, the Jarl will call you his / her head of the clan; meaning that you are now eligible to buy a piece of land under that Jarl's jurisdiction.

Step 5. Ask the Jarl about the piece of land they are selling
The Jarl will confirm the land auction. The Jarl will then tell you to speak to his / her assistant.

Step 6. Talk to the Jarl's assistant
You will now be able to buy lots.
Each lot is worth 5,000 gold and one of the conditions is a trip to its location
Advice
- Each lot requires the completion of all the tasks of the manager in those lands of the Jarl.
- Each piece of land is worth 5,000 gold.
- Unlike buildings, you will have to build a house on your own land; this means that as soon as you buy a lot, it is empty and you have to build a house from scratch.
- If you joined stormcloaks during the civil war, the Morthal Jarl will give you less of the clan leader quests you need to complete.