Thanks to all who answered my query. I will check each one and use the easiest/best one and let you know how it went.

Try the "watermark it" app

Go to befunky.com.

I'm quite sure that you can do this with online photo editors such as Canva. Craig (Labman) has created an excellent training video on using Canva: Customize a Header Image with Canva I use a photo editor called PaintDotNet. It's a free download that has many of the capabilities of more expensive packages. (Since I sometimes find myself without internet access, I tend to download standalone programs that I can use offline.)

I think you'll need to use some sort of photoshop app for that.

Thanks to all of you who responded to my query about how to incorporate a video into a post

Great, I was going to suggest you go to Marion Black's site. Dave

This should help Embed YouTube Video in WordPress

Hey.
When you have found the video you want to use on Youtube, there is a "share" button below the video.
First click that one and then click on "embed".
There will be a HTML link there.
Copy that link and paste it into the text editor of your post.
It is important that you use the text editor!

I have made a training that shows this.
I do show some advanced stuff there, which you might not need, but you will also see where I get the code and where I put it. Add Videos To Your Site With A Twist Add A Stop Command Here is another training that shows it: Easy YouTube Video Embed - No Plug-in Required Hope that helps.

Moritz