Any suggestions for a password manager app? I currently have MiniKeePass on my iPhone and although it does the basic job of storing passwords, I don't have the ability to create random passwords from the app itself and sync the changes to Dropbox. 

I'm looking for a subscription-free iOS app that had a clean, modern and beautifully designed UI. 

Any suggestions?
I use 1Password which is available for macOS (AppStore or directly from AgileBits), iOS, Windows and Android and offers both requirements you've listed (random passwords and Dropbox syncing).