Johanna is correct. The partnership could also do this without involving a third party. However, it is important to realize that draw is not necessarily taxable income - that amount is the partner's distributive share of various items of partnership income, expense, and credits. Some of that income may not be subject to ordinary income tax rates or self-employment tax. Furthermore, an individual partner's requirement for estimated tax payments may be affected by factors outside the partnership.
Draw is a reduction of the partner's capital balance which may include prior year income or partner contributions. Even guaranteed payments are not necessarily income to the partner - for example, in a loss year for the partnership, the partner could still receive guaranteed payments.
Partnerships are required to withhold and deposit tax for certain (foreign) partners. This is Form 945 withholding and the partnership would file Form 945 reporting the withholding and deposits. There may also be backup withholding withheld from payments to the partnership (e.g. interest or dividends earned by the partnership where the payer withheld backup withholding or any payments subject to backup withholding made to the partnership where the partnership failed to provide a W-9 to the payer or otherwise failed to provided a correct tax ID number to the payer.
The individual partner's share of any such withholding is reported on Sch K-1 in box 15 (Code O). The partner is to attach a copy of the K-1 to the partner's individual income tax return to show the amount withheld (similar to the way a W-2 or 1099 showing withholding is attached to the tax return.