Grammar Help: Should We Use "Has" or "Have" After "Management" and Why?

What should we use, "has" or "have," after "management," and why?

Thanks

The management is considered as one committee/body; whatever decision or rule is taken is unanimous, hence management is followed by "HAS"; grammatically speaking, it is taken as singular. Hope this explanation will suffice your requirement.

MANAGEMENT "HAS"

Origin & History
Management
1598, "act of managing," from manage (q.v.). Meaning "governing body" (originally of a theater) is from 1739. Manager is 1588 in the sense of "one who manages;" the specific sense of "one who conducts a house of business or public institution" is from 1705.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source

Management is a collective noun. We use the singular form of the verb with a collective noun like India, team, committee, Govt, etc. You can also refer to a grammar book to gain knowledge about collective nouns.

Regards,
H R Singh

Such words as "management" and "government" can take singular and plural verbs. Please consult the Oxford Learner's Dictionary of Current English.