English vs Japanese causative
English: I made him eat worms.
In other words:
A makes B do V Vobj = A が B に Vobj を V させる
The important part is that, in causative structure, what を attaches to is the object of the action, but not the causee (who is enforced). The causee is marked by に.
Thus, the given passage should be translated as:
The reorganization process through which different companies become one. There are: absorption-type merger, which lets another pre-existing company inherit the company's legal rights and obligations; and consolidation-type merger, which lets a new company inherit them.
(The legal information provided is, at best, of a general nature and cannot substitute for the advice of a licensed professional blah blah...)