Hi there @diposhenny1 , to answer your questions

1. Reblog works the same as any other other social media platform, the only difference being your content is open for everyone to see on Hive, so anyone can reblog your post. I wouldn't worry about the impact it has on your reputation and account as there is none, plus you have no control over what other people do. Worrying about your reputation is very premature and unusual for a newbie

2. Like any other social media platform, you can use whatever tag you want. Common sense dictates what they mean, like you wouldn't use the photography tag when you are writing a fiction or prose

I would recommend you to follow and read @newbies-guide, it has a host of useful information for newbies. You can also join The Terminal on Discord https://discord.gg/JugXKmgJ, they provide guidance for newbies.