Creating a series of identical objects could be difficult sometimes. Duplicating something manually may require a lot of time, and positioning those elements in a straight line could be also challenging. However, in Blender, there is a method you can use to make this process easier: the Array modifier.
The Array Modifier adds duplicates and moves your mesh several times in a non-destructive action. So, with the mesh selected, go to the wrench icon at the right of your screen to open the Modifier Properties Panel, click on "Add modifier," search in the Generate category for the Array option and click on it.
As you can see on the Array Modifier Menu at your right, you can add as many duplicates as you want on the Count option. However, if you go to Edit Mode and select the original figure, you will notice that the original vertices are still unchanged.
Blender, by default, will turn on the Relative Offset option to create a proportion between the original model and the setting of the Array Modifier. So, you can see Factor X, which is the value of the distance between the main object and its duplicates.
Note: Remember that Blender calculates the distance space from where the pivot point is located on your model. So, for example, if the pivot is just in the center of your model, you won't see duplicates when you set the value to 0. But, when you put the value higher than one, you will see the space between each duplicate.
Below Factor X, you will find the other axis names, which operate as Factor X. This is like a cartesian plane, meaning that If you set a positive value, the duplicates will appear on the positive side at the right or up.
Note: If you transform in any way your model, you are also affecting the space between each duplicate.
If you need a more accurate and realistic value, you can turn on the Constant Offset option, which will show you the distance of your figures in meters.
Also, to know how many duplicates fit in a determined space, go to the Fit Type option and select Fit Length. Then on the Length option, set the value you ought, and Blender will duplicate as many times as possible you need on that determined space according to the Factor or Distance X (or on the axis you set).
Another set you can use is the Object Offset option, which creates a duplicate at a specific distance. So, you need to create an Empty Object to save a coordinate. Then move your primary model as much as you ought. After that, select the Empty Object, which will create duplicates, but remember to set your pivot point.
There you have it! The Array modifier is extremely useful when creating groups of identical models!