They're really completely different. "Used to" is a phrasal verb that can mean either "in the past," or "become accustomed to." Examples: I used to live in Kiev. I'm not used to driving on the left side of the road in England. Note the grammar differences: to indicate that something was typical in the past, we use the present simple form of the verb; whereas to indicate that we are/are not accustomed to something, we use the gerund form of the verb. "Would" has many meanings and grammatical uses, including as a form in conditionals, as a modal, as the past tense of "will," etc. If you have a specific example, it would be easier to understand why you're confusing the two.

We use 'used to' or' would' to talk about repeated actions or events in the past which no longer happen. When I was young we used to/would go to the beach every summer (but now we don't do this anymore). But if we want to talk about repeated states or habits we use 'used to' not 'would'. 'I used to smoke.' 'My dog used to bark at cats all the time.' 'I used to live in London.' 'I used to be a teacher.' For questions and negatives we use 'use to' without 'd' 'Did you use to...?' .We didn't use to...' We don't use 'would' in questions and negatives because the meaning changes. 'When I was you I wouldn't play with dolls.' (This means I refused to play with dolls!) After to be, get or become 'used to' is an adjective and has a different meaning. We use it to talk about things that have become familiar and are no longer strange or new. 'After a while you get used to the noise.'

Those two expressions are only the same when referring to verbs that indicate whole actions or processes. When we were children,.... ....we would play in the fields. ....we would steal apples from the orchid. ....we would go to football games. All these expression can be used with "used to". You cannot use it with states. You must use "used to". We used to be good boys and girls. (not 'would')