You may be able to send a new application. You will not be refunded for this application. Therefore due care should be taken to ensure the application form is completed correctly and that you meet the eligibility and suitability criteria.
Before making another application, you should identify the reasons that your application was refused and understand if these are matters that can be corrected in your future applications.
For example, you may meet the criteria for ILR, but did not provided adequate documentary evidence, in which case you should ensure that for the next application the correct documents are provided. Another example is that you may have completed an incorrect section of the application form. In this case you should ensure that only the appropriate sections which apply to you should be completed and should be completed correctly.