That doesn't increase your BTC. 1BTC would still be 1BTC if you hold it. Just different amount in fiat when you convert it.

Here are the things I can think of that will make you get btc:
1. Signature campaign
2. Trading
3. Gambling
4. Offering services
5. Buying/selling goods
6. Lending
7. Investing in new projects
8. Currency conversion
9. Mining

It's kind of hard to trust people if they say that they can make your bitcoin grow fast. It sounds like another advertisement of ponzi site to me. You should do your own research. Some people would pretend that they're helping you when in reality they are just trying to rip you off. Just don't deposit or give people money or password and you'll surely won't get scammed.