The phrase "allows users to upload" is correct and usable in written English.
It can be used in contexts where you are describing a feature of a software application or website that enables users to submit files or data.
Example: "The new app allows users to upload their photos directly to the cloud for easy access."
Alternatives: "enables users to upload" or "permits users to upload".
Dubsmash allows users to upload and share mobile phone videos of themselves lip-syncing to audio clips.
It allows users to upload pictures of themselves and also of things they like that can convey their personality.
PalmPilot software also allows users to upload the images into their computers from their personal digital assistants.
Last November, Google launched "Google Base", a free service that allows users to upload anything including classifieds free of charge.
Ushahidi, an app that allows users to upload real-time data, helped Kenyans to protect their elections in 2013, and has since been harnessed elsewhere.
TabToolkit has similar features, but it allows users to upload digitized sheet music and tablature, so you're not confined to the app's song library.
Like Pampadour, Bloom allows users to upload pictures of hair, makeup and nail looks they've created, as well as tag the products they've used in those looks.
Ben Phillips, who has has 1.3m followers on the platform which allows users to upload six-second clips, told the Guardian: "It's like losing photo albums in a house fire".
There's no doubting the intention of I Change My City, from Bangalore in India, which allows users to upload a geo-tagged picture of an urban problem issue which is then reported to the city's government.
The so-called Music Reporter platform allows users to upload and download content relating to Vodafone-sponsored music events, via a MySpace page.
It has a feature called Find Friends, which allows users to upload their address book contacts to help find friends who are also using the service.
