From a procedural point of view: There is no problem in covering the blank space of the document.

From an industry norm (doing behavior) point of view: It is inappropriate to do so. risky.

As long as it is a document with the official seal of the company, it has corresponding legal effects, and the company needs to bear corresponding responsibilities, so there is a great risk in stamping the official seal on white paper.

When stamping in the blank space of a document, there is a possibility that the scanned or copied document will be forged. Because the text is not covered, it is easier to make changes, so stamping in the blank space also carries a great risk.

So the above two situations show that covering the blank space is very dangerous. This approach is not a special situation and should be avoided as much as possible.