I have galexy tab 3 7.0 SM_T210R when it's on standby mode charging normally but when i turn it off it doesn't charging anymore what's the problem??

Hi remove battery wait a short time before u replace it
then press & hold the power, home & volume buttons at the same time. Release buttons when Samsung logo appears
recovery option should come up on screen ........cheers

use another charger
and put on charger for long duration

Is this the one you have? If not what size screen does it have?
is there a model number? Support Wi Fi Tabs SM T210R Samsung Galaxy Tab
This is the link where you can download all the manuals for this version.

sign into your husbands account and read the book from the account it was bought under. i do not know if they allow transfers .

Hi,
to get your screen changed you can rush to your nearest samsung mobile service centre or you can go to any other mobile repairing shop. Thanks

Plug in your tablet, hold the power button while also hold downing the home button (white, black or silver button on front of tablet beside the return key) until the battery icon shows on the tablet. If this doesn't work and you are still under warranty send it back to Samsung. If no longer under warranty you will need to remove the entire back of the Tab and disconnect the battery from the motherboard. I do not give advice on doing this and you will have to look elsewhere for that procedure. I hope the simple fix works.

The charger has a function that restores the battery operation parameters by discharging then charging the battery a number of times. Refer to charging instructions in the pack but I think the cycle is a 3 hourly one, time to charge from a full discharge. If the charger thinks the battery is dead then it will try to recover the battery using this process. You may have left the charger on long enough to charge then also discharge the battery.
Start again and charge for the time in the instructions ONLY, if you are not sure of the time try it for an hour, then without disconnecting the charger turn the unit on and take particular note of any screen messages, if any.
You should be able to continue as normal now, but still be aware of the time you are leaving the charger connected for, as it may take some time before it returns to normal operation and stops trying to recover what it thinks is a dead battery.

You can select it first by touching the menu soft key and pressing select item! You can now select the picture in question then the trash can will appear top right

it's better for a suitable boot

It doesn't really matter which of these your select, it should charge regardless of which mode is selected as long as the USB cable is plugged into the tablet and then into the PC or wall adapter. I would recommend you pull out the battery and then put it back in.. if it still does nothing, you need to take it to get fixed, or you need to send it back to get fixed if the warranty is still valid.