Do I need to be physically present to apply for an eVisa and how does the 180-day stay work?

Hi everyone, I have a few questions:

1. After switching to eVisa, does the applicant need to be physically present in the country where they are applying? Can someone else apply for them from another country? (Both of them Not in Thailand)

2. If you leave and re-enter thailand without staying the full 180 days, does the 180-day period restart or accumulate? Or is it unlimited entries and exits within the 180 days from the first entry, with the requirement to leave or extend the visa before reaching the full 180 days? (The current extension policy seems unclear?)

3. Here’s the revised translation for the third question:

3. After obtaining the visa, is there a specific time frame within which you must enter Thailand?

Thanks 🙏