@ilyachaban ,
The tool reads a CSV file in the format;
<EPMDocument idA2A2>,<Global Attribute Internal Name>,<Reusable Attribute Data Type>,<Attribute Target Value>
The tool reads each line.
Finds the EPMDocument
Adds the value to the attribute.
The utility could be modifiy to use EPMDocument number rather than EPMDocument id. That would not be a problem.
Just spec out how you'd like it to work and I write it that way.
Note: the utility runs includes and -commit argument. If -commit is not entered no database changes are made. The run is logged but I like to make sure we are really ready to make changes therefore the I include explicit use of -commit.
I write lots of tools, if you need help feel free to reach out to me.
BTW, this is a hobby for me now. 20 years doing this stuff but retried now and just can't stop doing the fun stuff.
The help loos like this:

David
windchill.developer@yahoo.com