Adding and updating business listings

Can I add any business?
Can I add multiple businesses?
Can I update any business listing, even if it’s not mine?
How do I add a business?
How do I delete a business listing?
How do I review a business?
How do I update or make a correction to a business listing?
I don’t have a password, can I still make updates?
What are business tags?
What are location tags?