Cheah Hsun Teik, please avoid double posting, as it is against the forum rules. You can review our forum rules here. Thank you.
If you have something to add and your own post is the last one, simply edit it.
Is there any preinstalled software on microsoft window that can be used(like ms paint,but supports transparency and alpha channel) or a RPG maker MV script
simply: no
It cannot be done with a script, and Windows contains no program that can handle transparency correctly, you need to download another image program.
another problem,tileset not aligned
i searced the internet and it say my tileset is probably for parallel mapping
how to change it for normal mapping?
Basically you would need to open the tilesheet in an image program and reformat it.
Unfortunately that is not something easy for a beginner who never worked with tilesheets, autotiles or image programs, and if you don't have one installed then I assume you're one such beginner.
I suggest you make a post in resource requests, linking to the original page of the tileset you want to use, asking for someone else to reformat them for you.
Might take one or two weeks however unless someone already did this...