There is a funny tidbit on the Wikipedia page:

Although Ben-Gurion had told the audience that he was reading from the scroll of independence, he was actually reading from handwritten notes because only the bottom part of the scroll had been finished by artist and calligrapher Otte Wallish by the time of the declaration (he did not complete the entire document until June)

https://catalog.archives.gov.il/en/chapter/the-declaration-of-independence/

Because there was no time to spare, the Declaration was read from a mimeographed sheet, and the 37 signatories – members of the Provisional Council of State – signed their names to a blank parchment sheet. The official copy of the Declaration was later inscribed by an artist.

As for borders, by following the Declaration of Independence itself:

THE STATE OF ISRAEL is prepared to cooperate with the agencies and representatives of the United Nations in implementing the resolution of the General Assembly of the 29th November, 1947, and will take steps to bring about the economic union of the whole of Eretz-Israel.

The UN resolution called for an economic union of "Israel and Palestine", which would imply that "Eretz-Israel" was supposed to mean the whole land of the "Mandatory Palestine".

Prior to that:

ACCORDINGLY WE, MEMBERS OF THE PEOPLE'S COUNCIL, REPRESENTATIVES OF THE JEWISH COMMUNITY OF ERETZ-ISRAEL AND OF THE ZIONIST MOVEMENT, ARE HERE ASSEMBLED ON THE DAY OF THE TERMINATION OF THE BRITISH MANDATE OVER ERETZ-ISRAEL AND, BY VIRTUE OF OUR NATURAL AND HISTORIC RIGHT AND ON THE STRENGTH OF THE RESOLUTION OF THE UNITED NATIONS GENERAL ASSEMBLY, HEREBY DECLARE THE ESTABLISHMENT OF A JEWISH STATE IN ERETZ-ISRAEL, TO BE KNOWN AS THE STATE OF ISRAEL.

The British mandate was over the whole "Mandatory Palestine"... but the declaration talks about the State of Israel being "in Eretz-Israel", without specifying any explicit borders.

The "spirit" of the text can be interpreted as intended to follow the borders of the UN resolution... maybe.

Since the resolution clearly was not accepted by the Arab states, it would require some further analysis whether that means Israel is supposed to prioritize establishing an economic union of the whole land, or strictly follow the resolution.