$url=""  #自行填写网页请求地址
Invoke-WebRequest -Uri $url -Method get

需要传中文参数或者中文返回，需要使用借助System.Net.HttpWebRequest类

POST：

$url = ''  #自行填写网页请求地址
$body=@{
 "user" = $user
 "password"=$password
}| ConvertTo-Json    #具体参照接口参数修改
$webRequest = [System.Net.HttpWebRequest]::Create($url)
$encodedContent = [System.Text.Encoding]::UTF8.GetBytes($body)
$webRequest.Method = "POST"
$webRequest.ReadWriteTimeout = 5000
$webRequest.KeepAlive = $false
$webRequest.ContentType =  "application/json"
$webRequest.ContentLength = $encodedContent.length
$requestStream = $webRequest.GetRequestStream()
$requestStream.Write($encodedContent, 0, $encodedContent.length)
$requestStream.Close()
[System.Net.WebResponse] $resp = $webRequest.GetResponse()
$rs = $resp.GetResponseStream()
[System.IO.StreamReader] $sr = New-Object System.IO.StreamReader -argumentList $rs
[string] $results = $sr.ReadToEnd()

$Url = ''  #自行填写网页请求地址
[Net.HttpWebRequest]$WebRequest = [Net.WebRequest]::Create($Url)
[Net.HttpWebResponse]$WebResponse = $WebRequest.GetResponse()
$Reader = New-Object IO.StreamReader($WebResponse.GetResponseStream())
$Response = $Reader.ReadToEnd()
$Reader.Close()
$results = $Response | ConvertFrom-Json

想详细了解的可以看一下​ ​https://learn.microsoft.com/zh-cn/dotnet/api/system.net.httpwebrequest?redirectedfrom=MSDN&view=net-6.0​ ​