One of the easiest ways to track the jobs you have applied to is by creating a job tracking spreadsheet. You can do so in Excel or Google Sheets.
The column headings you should include are:
Company Name/Job Title
Job Posting URL
Contact Person/Title - use if you addressed the application to a specific person; include their title
Contact Info - phone number and/or email for the person or office responsible for collecting applications
Interview Details - include any specifics related to the interview, such as where it occurred, what you brought (an additional resume), etc
Interview Questions - include any questions you will want to ask during your interview; log the responses you received later
Follow Up Date - date on which you called or emailed to ask on the status of your application and/or thank them for the interview
Follow Up Format - email or phone
Status - offer, rejected, second interview, etc.