[voraa]

Как то так

function sendFile(){
        var subjectId = 'text';
        var lastName = 'text 2';
        var firstName = 'text 3';
        var thirdName = 'text 4';
        var companyName = 'text 5';
        var file=document.querySelector('#file').files[0];
 
        var dataF = new FormData();
        dataF.append('file', file, file.name);
        dataF.append('subjectId', subjectId);
        dataF.append('lastName', lastName);
        dataF.append('firstName', firstName);
        dataF.append('thirdName', thirdName);
        dataF.append('thirdName', thirdName);
        dataF.append('companyName', companyName);
 
        fetch('http://this-url',
            {
                method: 'POST',
                body: dataF
            }
        ).then(
                function (response) {},
                function (e) {}
         )
        
    }