1) Anyway England could conquer Mexico from Spain post 1521 .
2) What would be the impact of this ?
3) What would be the cultural effects
1) Depends on what the POD is (i.e. literally OTL up until 1521-22 for England to make the attempt, or something earlier?). If OTL till 1521, it's very VERY unlikely as not only was Spain on an upward military-industrial (for the time) swing, but England was just getting over the War of the Roses' aftermath and mostly focused on themselves, France, Scotland, and Ireland. An earlier POD (especially one pre-Black Death era) and it's anybody's game. Also keep in mind, in order to get (or at least keep) Mexico, you'd need Cuba as well since its location gives it a dominating advantage over commerce/travel to and from Mexico. Taking Cuba and Mexico from the Spanish is....well, dicey.
2) Depends on the nature and scope of the conquest, but IMO either Spain spends all the money/men to get it back (because '
aLL oF AmeRICa belONgS To hiS caTHoLIc majESTY!'), or if they accept/brush off the loss then probably focus on dominating South America (perhaps to Portuguese Brazil's detriment...maybe Tordesillas gets accurately adhered to?). And there's always Africa, India, and the North American Gulf Coast...
Meanwhile, England is in a position of 1-1 swapping with the Spaniards, and the question then becomes 'how well do they vassalize the native Mexicans' compared to the Spanish? Personally I sneer at the narrative that they'd just do "Manifest Destiny, 16th Edition", since that outlook and practice was overwhelmingly informed by OTL experience in 17th Century New England/Virginia, but something like how the East India Company was managed could arise (looking at the Irish Plantations as a model of example is a non sequitur since the population disparity is wildly different, even after all the plagues). So coastal trade posts with a central inland headquarters and a collection of Native 'princely states' and 'West Indian/Meshican' Company holdings.
3) With the above in mind, either Mesoamerican vocabulary, fashion, products, food, etc. gets internalized and adopted as new elements of English culture, or is regarded as 'exotic' and takes longer to make an impact domestically. Either way, a prolonged presence in Mesoamerica means a lot more exposure to a large, developed cultural milieu and some degree of diffusion (both ways, mind).