If you make videos by yourself and want to protect your work, make it more distinguishable and even professional, you should consider adding your signature. Actually, lots of YouTube gurus seem be doing so.

Here is how I do it with the video converter I have been using.

Step 1: Add Video

Add the video files you want to watermark with text or logo picture.

The converter I am using is Any Video Converter. It is a pretty famous and useful tool. You can download it from http://www.any-video-converter.com/products/for_video_free/
Note: This converter is totally free, when you install it, it will recommends another software to you, make sure not to check it in the install process.

Step 2: Click "Add Effects" Button and Choose "Video Watermark"

Refer to the screenshot to find the "Add effects" button, clicking it will get a popup. There are 3 tabs in the popup. Choose "Video Watermark"

Step 3: Add Watermark

You can choose to add a text watermark or picture watermark. Also, you may add edition to the text and picture to make it more special. When all is done, click "OK" or "Apply".

In this screenshot, I am adding text to the Youtube video I made.

Step 4: Click "Convert Now!" to Make This Effect Done.

Before you click "Convert Now!", you may choose the output format first. You may change the format or retain the original format.

Note: If you do not click "Convert Now" to make this proceed, the watermark you add will not added to the video.

Step 5: Check If the Watermark Is Added Successfully

When conversion finished, you can simply find the output video to see if watermark is added successfully.

Simple, right? Have a try now and let me know if it works for you!