There’re three ways to remove the watermark from your video.
First, you can register an Apowersoft account through their programs or the community (you’ve had one if you can post here, right?), then you will get a 3-day VIP account. During this period, you can enjoy all their programs without any limitations. But, after 3 days, your programs will be trial version?
Second, you can ask for a coupon-code from Apowersoft Support . Generally speaking, they will send one to you if the program is for educational purpose?
Third, get a cracked version(not recommended). It may include virus which can damage your computer. So, you’d better download program from their official site.