I am looking for a solution where in desktop 4 column and in Mobile it will be 2 columns
I tried this solution from 
CodePudding user response：
Bootstrap has removed all @-xs-* classes in version 4 . So there isn't any col-xs-* classes. Use col-6 and col-sm-3.
<link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.0.2/css/bootstrap.min.css" rel="stylesheet" />
<div class="row">
<div class="col-md-3 col-6">
<h3 class="news_let">
Resources
</h3>
<ul class="ft_conte">
<li>
Desktop Client
</li>
<li>
Mobile apps
</li>
<li>
Form Center
</li>
<li>
Margin File
</li>
<li>
Margin Calculator
</li>
<li>
Brokerage Calculator
</li>
</ul>
</div>
<div class="col-md-3 col-6">
<h3 class="news_let">
About the Company
</h3>
<ul class="ft_conte">
<li>
About Us
</li>
<li>
Blog
</li>
<li>
Privacy policy
</li>
<li>
Term of Use
</li>
<li>
Complaint Book
</li>
<li>
Contact Us
</li>
</ul>
</div>
<div class="col-md-3 col-6">
<h3 class="news_let">
Careers
</h3>
<ul class="ft_conte">
<li>
About Us
</li>
<li>
Blog
</li>
<li>
Privacy policy
</li>
<li>
Term of Use
</li>
<li>
Complaint Book
</li>
<li>
Contact Us
</li>
</ul>
</div>
<div class="col-md-3 col-6">
<h3 class="news_let">
Legal
</h3>
<ul class="ft_conte">
<li>
Investor
</li>
<li>
Privacy policy
</li>
<li>
Risk & Compliance
</li>
<li>
Policy
</li>
<li>
Disclaimer
</li>
<li>https://srv.buysellads.com/ads/click/x/GTND42JIC6BIC23MC6SLYKQNCKYI42QMCT7IKZ3JCY7I4KQUFTYI62JKCYSD42QJCEBI523NCEYDK2QUF6BDKK3KC6SDCKQMCKADTK3EHJNCLSIZ Filling of Complaints<br/> On SCORES
</li>
</ul>
</div>
</div>CodePudding user response：
You did it right, but a class is missing. add "col-sm-6" to all