If you have necessary AWS credentials

export AWS_ACCESS_KEY_ID="XXXX"
export AWS_SECRET_ACCESS_KEY="YYYY"
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you can install aws cli with

pip3 install --user aws
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and create an S3 bucket from command line without opening a web browser.

aws s3api create-bucket --acl public-read --bucket my-unique-bucket-name --region eu-central-1 --create-bucket-configuration LocationConstraint=eu-central-1
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which will create a bucket readable by public in http://my-unique-bucket-name.s3.amazonaws.com.

Then you can copy your files with

aws s3 cp my-file.zip s3://my-unique-bucket-name/subdir/my-file.zip
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and share the link, http://my-unique-bucket-name.s3.amazonaws.com/subdir/my-file.zip with anybody you want to share the file.