It'd probably help to let our more techie people like rubl know what phone and scanner you have.

Depending on the smartphone you have and the scanner you have it could be possible. The scanner may well take a USB port connection which can be connected to the phone. USB cable connectors are easy to buy from places like Powerbuy. I even recently bought a USB connector in 7/11 that is a generic USB at one end and then with half a dozen plugs to put in the other end that will fit iPads, iPhones, mobiles. It can be used to connect to powerbanks, car chargers, or anything else with a USB port. Key is the USB connection though.

You may need an app though to get it to work. If you look up the make of the scanner and search in your app store on your phone there may very well be an app for the specific scanner you have.

Also certain smartphones have a scanner function anyway, so you could use the phone directly as a document scanner if that's the case.

Bit puzzled though why you don't just scan them all to a PC and then copy all the files en mass from your PC to your phone, if you really want them on a phone?

BTW We have a wireless printer. It's a Brother MFC-T800W. Cost around THB 6 or 7k. Works great. It can either be connected to a PC directly with a USB cable or used Wireless with the PC, an iPad, Iphone, Smart Phone etc. It's an all in one printer, fax, scanner. I have a Samsung Android phone. I downloaded a "iPrint &Scan" app by Brother from Google Play store and can print directly from my smart-phone - all done wireless. Haven't tried scanning, but the app on the phone shows it as an option 

welcome.brother.com/th-en/products-services/multi-function-centres/MFC-T800W.html

To be honest though I'd still scan everything to PC and then copy from PC to phone, as it's easier, gives a back-up on the PC and storing on the PC doesn't take up all the phone storage. Also quicker I think as the processing power/CPU and memory etc on the PC is better than on the phone.  

BTW2 Another option we had on an older HP printer/scanner that wasn't wireless was that it can scan direct to an SD card. If we used an SD card with a SD micro adapter We could then either insert the MicroSD card part into the phone - if your phone takes them. Or I used to copy the SD card to the PC, and copy the PC to the phone memory or microSD on the phone. Ability to scan direct to a SD card is less common these days 

So I guess let us know what scanner and what phone you have

BTW3 One other very simple solution - depending on the quality you're looking for - is simply use your phone/ tablet etc to take a photo of the photos. If you're just sending them for someone to take a look and remember this is often fine. You can then email them or share via FB, Line etc.

The main thing is keeping your hand steady and focusing the phone camera. A stand or similar for your phone or tablet could be useful. I often do this as a quick method.

Forgot to mention. The memory card + adapter/ Micro SD card now come in 2 speeds: Class4 and Class 10. Class 10 is newer and faster and more expensive. Think most devices can use Class 10 these days, but not sure on some older stuff. I have Class 10 Micro SD and adapter and my phones around 3 years old. If in doubt go to a phone shop and ask to try in your phone. All mobile phone shops sell them