If you are using Adobe Acrobat and when you download a PDF it is automatically opening, and you do not want it to, please try these settings.

In your web browser (Chrome) 

1. Click the three dots (⋮) in the top right corner and select Settings. 
2. Go to Privacy and security, then Site Settings. 
3. Scroll to "Content" and select Additional content settings, then PDF documents. 
4. Choose Open PDFs in Adobe Acrobat (or another app) instead of downloading them. 

In your web browser (Microsoft Edge) 

1. Click the three dots (⋮) in the top right corner and select Settings. 
2. Go to Cookies and site permissions. 
3. Scroll to "All permissions" and select PDF documents. 
4. Toggle off the "Always download PDFs" setting. 

On your computer 

1. Right-click a PDF file and select Open with > Choose another app. 
2. Select your preferred PDF application (e.g., Adobe Acrobat Reader). 
3. Check the box that says Always use this app to open .pdf files and click OK. 

In Adobe Acrobat Reader (Windows) 

1. Open Adobe Acrobat Reader and go to Edit > Preferences. 
2. In the "Categories" list on the left, select General. 
3. Click the Select Default PDF Handler button. 
4. Choose Adobe Acrobat Reader DC and click Apply. 

Alternatively have a look at this link