Congress last night approved and sent to President Reagan a $7 billion catch-all appropriations bill for the rest of this fiscal year. The measure is needed to avert a delay in food stamp payments to thousands of poor people on Monday.

So urgent was the food stamp funding problem that the Reagan administration and its Senate Republican backers temporarily shelved their demand for inclusion of $8.4 billion for the International Monetary Fund to help alleviate the debt crisis of Third World countries.

The problem arose when the House passed its version of the bill after voting 213 to 165 to reject the IMF money until it finishes considering an authorization for the IMF funding. The Senate faced the prospect of a weekend deadlock that could jeopardize food stamp payments due Monday if it insisted on the IMF money.

"There is no escaping the fact that . . . this bill must be sent to the administration tonight," Senate Majority Whip Ted Stevens (R-Alaska) said as the Senate began consideration of the measure.

The Senate approved the measure by a vote of 49 to 25. The House voted 257 to 133 give advance approval to the overall measure Thursday night and gave final approval to contested provisions before the Senate's vote yesterday.

Although the administration wanted the IMF money and objected to some spending that Congress did approve, "We assume the bill will be signed," a Senate Republican leadership aide said. The aide said the administration and congressional leaders believe another way can be found to appropriate the IMF money.

The bill provides $1.2 billion to continue food stamp payments through the end of the fiscal year, Sept. 30. The Department of Agriculture had been telling states to issue new food stamps on the assumption that Congress would act before the Aug. 1 deadline, but an official said yesterday that 10 to 15 states that had not yet issued them faced a delay in payments early next week.

"We scrounged all we could . . . . We'd be down to zero on Monday," said Duane Maddox, assistant to the deputy administrator for family nutrition programs.

In addition to the food stamp money, the bill--presumably the final general appropriations measure for the 1983 fiscal year--provides $25 million in new military assistance to El Salvador, half of what Reagan requested. Congress earlier reprogrammed another $30 million for El Salvador, also half the amount Reagan wanted.

The bill gives senators an annual pay raise of $9,138 but restricts their earnings from speechmaking and related outside activities to $20,940 after next January. The pay raise brings Senate salaries to $69,800, which is what House members approved for themselves last year.

Senators last year opted for unlimited outside earnings instead of a pay raise. But they were so embarrassed by the huge moonlighting fees some of them received that they went along this year with a House proposal to limit speech-making fees. Then senators decided to take the pay raise.

"The disclosure this year of how much they've been raking in from honoraria has shocked us all," Rep. Silvio O. Conte (R-Mass.) said as the House voted 224 to 107 to go along with the Senate pay raise and outside earnings limit. Other members also conceded privately that the honorarium limit was pushed by House members to squeeze senators' income enough to get the Senate to go along with the House in voting periodic pay increases.

On another contested issue, the House voted 204 to 191 to approve a provision aimed at protecting cotton growers from financial losses that they anticipate from the administration's payment-in-kind (PIK) acreage-reduction program.

The proposal, slipped into the bill at the last minute by cotton-state lawmakers and characterized by Conte as a "bailout" for big cotton growers, added about $100 million to the bill and drew fire from the administration, although apparently not enough to prompt a veto.

The legislation also dropped a House proposal for a moratorium on federal coal leasing in favor of a commission to review the often-criticized leasing practices of Interior Secretary James G. Watt.

In what appeared to be an initial victory for Reagan's strategy of forcing spending cuts by threatening vetoes, appropriators from both houses last week scaled down their spending proposals to get within limits set by the White House.