When Allah (SWT) refers to Himself in the Qur'an in the form of a verb, He uses the plural form. As in "We Created", "We Said", "We Helped". Why does He use a "We" yet when He refers to Himself as in names or actions that are required from us, He will use the single term, as "Worship Me", "Fear Me"?

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

The Qur'an was revealed in Arabic. Arabs use many rhetorical styles. Among these styles is the use of 'We' instead of 'I' in order to show glorification on the part of a speaker.
This style is common in the Qur'an. Here are some examples:
Allah Says (interpretation of meaning): {And indeed We created the heavens and the earth and all between them in six Days …}[50:38]
Allah also Says (interpretation of meaning): {And (remember) when We said: "Enter this town (Jerusalem) ….}[2:58]
Allah also Says (interpretation of meaning): {And when We decide to destroy a town (population), We (first) send a definite order (to obey Allâh and be righteous) to those among them [or We (first) increase in number those of its population] who are given the good things of this life. …}[17:16].
As for the words "'Abodoon: You have to worship Me" and "Khafoon: fear Allah" and the like, they represent forms of instruction and order, not forms of notification and informing.
But, in case of singular imperative we use the singular "I", not "we" if we intend glorification.
Allah knows best.