in my project the client sent me this info about wind:

a-direction of prevailing wind, from west
b-maximum average speed, 115 km/h
c-design wind load 1.4 KN/m2

How can insert this datas in my caesar model?

If you want to use the specified load (1.4), enter that as a uniform load in the appropriate direction.

If you want to use one of the wind standards, where the load is computed based on the velocity (115), you do that on the "Wind" tab in the Static Load Case Editor.

Anyway 115 km/hr corresponds to a pressure about 0.7 kPa so the option to use "design pressure" is natural because it is likely that any algorithm to get "gust" based on "average" will be finalized with a factor less than 2 . In addition, the term "maximum average speed" is so vague- you can find an interesting discussion on averaging subject in https://www.wmo.int/pages/prog/www/tcp/Meetings/HC31/documents/Doc.3.part2.pdf

So i can insert wind in Static Load Case Editor as pressure or velocity.
But do i have to insert the SAME pressure (or velocity) at different heights?

ex., if i choose to use pressure:

10m: 1.4 KN/m2
20m: 1.4 KN/m2
30m: 1.4 KN/m2
40m: 1.4 KN/m2
50m: 1.4 KN/m2
...
100m: 1.4 KN/m2

where 100m is the higher part of plant.

In case you indeed have to calculate wind effects at elevation 100 m above ground, you need more accurate data about wind definition. Your data miss to be clear as they are at elevation 10m, as it is supposed to be. A wind elevation profile as power law with exponent 1/7 was popular in the past but has been found it's fair only during near-neutral (adiabatic) conditions.
IMO you need more accurate wind basic data and follow a Code like Eurocode or ASCE to develop the calculation.