As well is an adverb which means ‘also’, ‘too’ or ‘in addition’. We usually use as well at the end of a clause:
We look forward very much to seeing you again and to meeting your wife as well.
As well as is a multi-word preposition which means ‘in addition to’:
She has invited Jill as well as Kate.
When they go to Austria, they like walking as well as skiing.