paid tax entering problem

Personally, I would simply enter a journal,

ie.  Debit Tax Control Account - Credit Bank Account

(this assumes that I owe the tax authorities monies rather than reclaiming tax from them, in which case the journal would be the opposite of the above)

Xero

I am sure that there will be more wise and experienced people in this forum who can give you further advice about this.

However, in my experience, when using the Tax System in FA, it is crucial that the set-up is done in such a way as to properly and correctly record your transactions in accordance with the taxation laws and rules that apply to you. In my case, I have to follow VAT in the UK, which operates on the basis much as you have described in your above post (ie in simplest and most basic terms, you pay the net difference to the tax authorities, of what you have paid to your suppliers and collected from your customers).

If however (as you appear to suggest above) that you wish simply to record a tax on Sales only, then I suggest that you set-up a separate tax control account for Sales-Tax only in your General Ledger, Set-up the Tax in Tax module, and then set any Items appropriate for those Sales which attract the sales tax. You may of course if you wish, also separately follow Purchase taxes in the same way if desired, but this would IMHO ideally need to use a separate General Ledger control account, and further entries in the Tax Module, and relevant Item entries as well.
Once all the set-up is done in such a way (recommend that you try to follow the Wikki), then you will be able to accurately report on each of the taxes that you wish to follow with the tax reports and other relevant reports.

Perhaps if you can tell the forum where-abouts in the world you are, then there may well already be people here who have a more intimate knowledge of your local taxation requirements and how to set them up in FA.

Hope that helps

Xero