I'm pretty sure OP is talking about a screen recording where part of the process is filling in a form with a phone number or credit card or some other personal info. It appears OP wants to blur out that private stuff.
Are you talking about a watermark? If so, here's what I did in my first course which I just submitted for review.
I use Davinci Resolve (free) to edit my videos. You need to search online for transparent PNG maker. Then you can use it for your logo or website. I wrote out my website URL. Then you insert it into your video. The 'transparent' part makes it so only the words appear and not any white background.
Then you use your editing software to lower the opacity of the image until it is visable but still a little transparent. Place where you want and, boom, watermark.