The Carter administration announced the outlines of a welfare reform program yesterday that would guarantee jobs for people who can work and cash assistance to those who cannot.

Carter told a news conference that the present welfare system should be scrapped but said his new one probably will not be put in place for four years.

He also laid down an edict specifying that the new system must not cost more initially than the present assortment of programs.

The President said that a 3-month assisment by the Department of Health. Education and Welfare produced the conclusion that welfare now "is worse than we had anticipated."

"The most important unanimous conclusion is that the present welfare programs should be scrapped and a totally new system implemented," he said.

Although many features of the plan remain unresolved with the administration. HEW Secretary Joseph A. Califano Jr. and Labor Secretary Ray Marshall provided these details:

Every family with a child and a member able to work would be guaranteed a job - a publicly financed one if private employment is unavailable. Money from the present public-service jobs program would be diverted to make those jobs available.

A number of present assistance programs would be consolidated so that recipients who cannot work would be eligible for a single cash payment. The assiatance would follow uniform national standards, varying only by the differences in cost-of-living from area to area.

The so-called earned income tax its already in the tax law would be retained to help the working poor - those who held jobs but do not make enough to live on.

During the campaign last year, Carter listed welfare reform as a priority undertaking and at one point indicated be expected to have a program ready early this year.

A number of problems have intervened to delay the preparation, however. There are differences within his administration over many key details. HEW had leaned toward a program emphasizing cash assistance and expected to cost the federal government between $6 billion and $8 billion. Labor had pushed for a system relying mainly on creation of public-service jobs.

Congressional leaders have also made it clear they will not be able to consider welfare reform this year. The two committees with jurisdiction - House Ways an Means and Senate Finance - will be preoccupied with other pieces of Carter's legislative program, including tax reform, energy legislation, and a possible restructuring of the Social Security system.

Carter said yesterday that the legislative proposal will not be ready until August. "If the new legislation can be adopted early in 1978, an additional three years will be required to implement the program," Carter told reporters.

Potentially the most important element in what was disclosed yesterday is the promise to guarantee jobs to families with children. Carter said it might involve providing as many as 2 million jobs. Marshall said later the actual requirement might be much less, possibly only a million.

The public-service jobs would include employment such occupation and agency as teachers' aides. Department of Agriculture extension service, aid to the elderly, and recreation centers, Carter said.

The program could cost as much as $6.000 per job. Marshall estimated. The money would come from the public-service jobs part of the economic stimulus plan proposed to Congress in January. It is by using that money that the administration could provide the expensive jobs-creation program and stay within Carter's injunction that the present level of expenditures not be exceeded.

The other major element, as described by Califano, calls for consolidating into a single cash-assistance payment the benefit's now available under three major programs - Aid to Families with Dependent Children, food stamps, and Supplemental Security Income, which is federal welfare for the aged, blind and disabled.

How those consolidated sums would compare with the benefits available under the present separate programs has not been estimated, administration sources said.

There was no indications yesterday that the planners had satisfied the pleas of state and local governments for relief of their welfare burdens. Carter said only that those burdens should be reduced "as rapidly as federal resources permit."

Another unresolved issue, the sources said, has to do with who should be required to accept jobs offered them. Califano said that a system of penalties and incentives would be used to encourage welfare recipients to take jobs, but the issue of a mandatory work requirement is still being debated. A large proportion of welfare consists of women with children. Califano said no decision had been reached on whether to require months of young children to take jobs.