it depends
a country that has over 25m pop can transfer pop down to that level, meaning, if you have 25.7M pop in a conquered country, you can transfer out 700K, with a limit of up to 1M per game month
as far as resources, yes. a country can transfer money, as long a it doesn't not go to a negative. that is, if it has 800B in cash, and 120B in loans, it can transfer out 680B, max you can transfer out per game month is 3m
further, as long as the country has a positive cash balance (or if it only has a small negative,) you can transfer weapons and ammo out. but that counts against the normal military spending of the receiving country. this how ever is an advantage, as it is transferred at a reduced effect. infact, the best way to build military fast, is to conquer a computer controlled country, C3, and buy weapons and ammo their (probably transfer money INTO the C3) and then transfer out the military hardware. you can transfer upto 3 times the normal amount into a country, than you could normally buy.
as far as regular goods, you can set direct sales from the conquest, to the conquerer, buy them, and transfer the money back, but that is rather time intensive. if you are bran new, it might be worth it for your first few conquests, but eventually will be to tedious
also, i'm assuming you conquered a C3 near you. if you transfer in say 5000 jeeps, use them to set up supply units, and then set the garisons to "undefended," after a few game months, all the defensive weapons and ammo you didn't destroy while taking the C3, will become avaible to be transferred out. (you may need to dismantle you supply units, and will need to wait atleast a game month.) another trick to this, is to get the supply units set up and set the garisons to "undefended," asap. as targets that you destroyed, might have weapons/ammo left, but only for a short time, before they disappear. (usually around the 15th or end of the month,)
you will find the option to transfer, under "empire," their will be three options to transfer, they are all the same, it doesn't matter which you pick