After the download finishes, you can verify it with one of these checksums:

md5: 91ac96013f9d510f139291657d74ed30
sha256: 53a217be4a046b469d090fe4b34fd628a34ef6250050e52f255d91343788a663
sha512: 0396f7e3adf16778d4591293dd944e107bbbbe203e03448926148daabb2f699bbc935b9e73ec7289adb201b5a29762546a0eca49b4cc6a4ec610668a4f4c63f6

For example, on Linux or MacOS, open a terminal and type:

cd Downloads
sha256sum vivado-manjaro.ova

This will take a bit as it has to read the entire file.
Compare the output with the sha256 number listed above.
If it doesn't match, then your download was faulty.
If it does, you're good to go!