The free program on the windows store is"pdf merger and splitter" from anywaysoft

DID NOT GET "PRO" version as stated.

According to the description it should be able to merge multiple PDF files into one !

The application is useful. The first feature I tested - whether the resulting PDF remains editable or is it saved as a bitmap. The answer: it remains editable.
But I also see a number of problems with this program.
1) The most annoying - each time you merge the pages the program opens the folder where the resulting file is saved to. And you cannot turn this off. This must be optional;
2) If you save second version of the merged pages the program overwrites the previous version. There should be an option to either overwrite the previously saved file or to save new version under a different name, like filename(1).pdf;
3) If two pages you merge are not of the same size and orientation the program rotates one of the page to fit instead of keeping the orientation. Again, there should be an option to keep the orientation: although there is an option 'Rotate pages', the result is the same whichever option you select;
4) There is no custom output page size;
5) Although the program remembers the output folder when closed and re-opened, it forgets the last used page size;
6) You cannot close the file without closing the program. To select another file to merge you have to close the program and re-open it. Unprofessional.

Downloaded and installed effortlessly. Thanks for this giveaway

I thought this was going to merge multiple PDF files into one file. Instead, it combines all of the merged files onto a single page. Not useful for me.