SharePoint Online: Delete Column from List using PowerShell

• Go to List settings by going to List tab >> Under Settings group, click on List Settings button in the ribbon.
• Under the List Settings page, in the Columns section, click on the column title you wish to delete.
• Scroll down and Click on Delete button.
• Confirm the deletion prompt by clicking OK.

#Load SharePoint CSOM Assemblies
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

#Variables for Processing
$SiteURL="https://crescent.sharepoint.com"
$ListName= "Projects"
$ColumnName="Project Code"

Try {
    #Get Credentials to connect
    $Cred = Get-Credential
    $Credentials = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($Cred.Username, $Cred.Password)

    #Setup the context
    $Ctx = New-Object Microsoft.SharePoint.Client.ClientContext($SiteURL)
    $Ctx.Credentials = $Credentials

    #Get the List
    $List = $Ctx.Web.Lists.GetByTitle($ListName)

    #Get the Column to delete
    $Column = $List.Fields.GetByTitle($ColumnName)
    $Column.DeleteObject()
    $Ctx.ExecuteQuery()

    Write-host "Column '$ColumnName' deleted Successfully!" -ForegroundColor Green
 }
Catch {
    write-host -f Red "Error Deleting Column from List!" $_.Exception.Message
}