Then you'll just send a jpeg file as usual, to the magazine. And yes, make sure it's 300ppi as they asked.
For web, maybe you just need to do what they say. Don't resize them at all, just crop two versions for them.
You'll have to ask them. Every website is different. They'll need to tell you exactly what pixel dimensions their website requires.
Resolution is completely irrelevant for web images. It can be 300, or 72, or 3000000000, or 7. Only the pixel dimensions matter.
https://www.damiensymonds.net/2010/10/how-ive-been-sharpening-for-web-lately.html
PDF? Are you sure? Can you show me exactly what their requirements say?
Yes, you gave me exactly the right screenshot.
Also, your Clone Tool is set to "Current Layer" in the Options Bar. That's bad. It must always be set to "Current & Below".
Don't forget that straightening (if required) should be the very first step in Photoshop. https://www.damiensymonds.net/2010/01/straightening-horizons.html
I have no idea, sorry.
But I'm so excited for you. I'm so excited to see your photos with better focus. Your magnificent photography has been let down for the longest time by poor performance at high ISO.