Terms of specific mergers or acquisitions must be disclosed in the company's 8-K report to the SEC. (8-K reports must be filed within four days of the triggering event)
Terms can also be included as exhibits to the the company's 10-K or 10-Q reports.
If the merger or acquisition requires a vote by shareholders, the agreement will be available in the proxy document, Schedule 14A.
Research the debt and equity financing history of public companies with one of these databases: