MCI Communications Corp. announced a 2-for-1 stock split yesterday after shareholders approved an amendment to MCI's certificate of incorporation increasing the number of the company's common shares from 200 million to 400 million.

Chairman William G. McGowan told shareholders the company has a "megachance" to build its telecommunications business into a world leader in "the information age."

"MCI is indeed the right company in the right industry at the right time," said McGowan. "We know what we want to become: the low-cost leader in serving this new information economy."

The company earlier reported revenues increased 112 percent over the preceding year to a total of $1.07 billion. Net income rose 98 percent from $86 million in 1982 to $171 million in fiscal 1983.

MCI's president and chief operating officer, V. Orville Wright, told shareholders that, although MCI is primarily a long-distance phone service, it is "broadening into the full-spectrum telecommunications company."

He cited as examples the company's acquisition of Western Union International last year for international communications markets as well as the company's cellular mobile telephone venture.

With the onset of the breakup of the Bell System, MCI is now negotiating with the seven regional operating companies that will become independent next year, Wright reported.

These companies would be the gateway to the "local loop which leads to the sort of long distance service that MCI currently provides." Wright said.