Hooookay; (warning: ramble n rant)
What I’m about to type only applies in the US. I’m not a licensed electrician, but I’ve mucked around enough with being a handyman/general maintenance type person who knows their exact limitations as far as when to put the insulated screwdriver and chicken stick down and call a proper sparky to set my house on fire instead of trying to do it myself. YMMV.
Swapping two hole outlets with three holers: Only do this IF (and only if!) there’s an actual ground wire IN THE BOX. In the US, White is the neutral (return) line, black (or red, blue, or rare cases white with black stripes) will be the live wire. A bare copper line or green is the earth ground.
If there’s no ground, you might be able to get away with it IF the box is metallic and grounded. Buy an outlet tester, it’ll give you the rundown on if you need to have the place rewired. The nicer ones also have a button which will test the GFCI outlets as well, and the tool is worth having in the house tool kit.
Along that line: Houses built from the 60’s onward will usually have a ground line. HOWEVER: current code dictates that the earth ground be the same wire gauge as the power and neutral lines; houses from the 60’s and 70’s… don’t, unless the house got re-wired in the intervening decades. (my house was built in '61, and has a 14 or 16 gauge ground line with 12 gauge power and neutral. It was code back then, but it’s not now, and if I was doing major work on the house, I’d have to remediate it, which is… expensive.)
If there is no ground line and the box isn’t grounded in some manner, be resigned to calling in the pros to either re-wire the house or figure some other arrangement. Use a licensed and bonded electrician, they are generally worth the extra spend over the long haul.
Regarding running low voltage DC power lines for “future use”:
TL;DR: Don’t. Just don’t. The poor sod who comes after you will end up insulting your family for the seven previous generations before ripping it all out. For powering USB, swap the outlets for ones with built in chargers.
On a side note, you can (and probably should!) run low voltage data and signal lines around, with a few given limits. the Big one is this:
LOW VOLTAGE LINES MUST BE SEPARATED FROM POWER LINES. The reasons for this are for twofold: EM interference, and accidentally running high voltage down a line that wasn’t designed for it and setting equipment (and your house!) on fire. (I mean, we all like hearing a 60 Hertz buzz on our speakers, right?)
If you want to run low voltage lines around the house to ‘future proof’ the place? sure, if you are running Cat 6 cable for networking.
There are boxes designed for low voltage cabling (the keywords are “Structured cabling enclosures”) and will hold audio cabling, ethernet, coax, and fiber if you are insane or are running a 10GbE backbone between rooms. They also have an option to have an outlet attached to it to power things like cable modems, wired routers, switches, coax signal amps, etc.)
When I bought my house, one of the things I knew I could do was to swap the outlets around, because it’s a good general principle. Plus, the old outlets were loose, and the old ‘push wire in, pray it holds’ style from the 70’s or 80’s. I also trashed a couple sawzall blades and put in one of the aforementioned structured cabling enclosures, and ran ethernet and coax to it from various rooms. I did pay for an electrician to come out and do a few specific things with the house wiring, because they were all outside my wheelhouse of ability, and I wanted it done in a timely and professional manner.
As noted upstream in these comments, buy a well known brand for in-wall outlets, be they GFCI, Power with USB chargers built in, or even low voltage jacks. These things will be used on a daily basis and need to last for years, possibly even decades. Some no-name or six character ‘brand’ from Amazon might save you a few bucks, but if it causes your house to burn down, that’s something you’d really not want, especially when the insurance company denies the claim because the company that sold it no longer exists and the device was never UL listed. And I care for you happy mutants, even if I don’t agree with all of you all the time.
Personally, I’m partial to Leviton for power and datacomm products, but pick something well known from either the local hardware store (including the Orange or Blue Monsters) first before hitting up the Amazons.
And on that note, Have a good evening and take care.