My Keyboard automatically adds a period if I click twice. I use a custom keyboard called Go Keyboard. Not sure if you can make the default keyboard do it.
There's a version of M$ Office for Android, but it requires paying for an Office365 subscription. Which you can get for $80/4yr sub.
https://play.google.com/store/apps/d...fice.officehub
I use a knockoff called Kingsoft Office. Works decent enough for the price. But I don't do a whole lot of mobile work, just very simple editing. It also allows you to manage pdfs.
https://play.google.com/store/apps/d...ps.moffice_eng
I really like Chrome.
Hold down the Home button to get to the Task Manager. You can kill apps there.
You can also get apps like JuiceDefender, that does a bunch of stuff to preserve battery. But I found most of those apps to be such a pain in the ass that I preferred to simply manage running apps manually.
Voice works really nicely. It's a Siri clone. I use that very frequently. If you're running stock Samsung, it will be S-Voice. You can configure it to whatever button combination you want.
Titanium Backup is a nice app. Used for backups, app management, freezing apps, etc.
TeslaLED is a flashlight app that turns your camera flash into a flashlight.
CardStar lets you store all your Shopper cards on your phone.
AroundMe is handy for finding nearby places of interest.
Just a few I can think of.