Which idiom is correct - allows for or allows to?

"Allow for" and "allow +object + to + verb" have different meanings.

"The new budget allows for unexpected expenses." Here, "allows for" means "leaves room for the unpredictable" or "gives leeway."

"He allows me to eat hamburgers on Wednesday." Here, "allows + object + to" means "gives permission."

And another use of "allow": "I allowed that there might be another option." Old-fashioned American slang meaning, "admitted that."

Please note that the construct "allows to + V" is generally considered non-standard English, and should rather be expressed in gerund form: e.g., "allows eating", not "allows to eat".