We can upload files in Jenkins using the "File Parameter" option.
Step1: Click on the Configure button of Jenkins job.
Step2: Click on the Add Parameter drop-down and then click on File Parameter.
Note that the file will be uploaded to the workspace of this job. If the file need to be uploaded on some custom folder, specify the same in the box "File location" while configuring parameter. Here we need to put the filename too, so that whatever file uploaded, it will saved with this given name.
Step3: Put description if needed.
Step4: Click on Save
Now the job is ready to accept files as parameter for upload.