Automatic Data import

Hi Florent SEGUI,

There are many ways to do this. Do you want to ijmport the data from the external sources or do you want to reference the data.

You could use external lists using the BDC/BCS to talk to your databases. Please be aware of this in Office 365. I've seen very poor performance on very wide tables.

You could use an import scripts (PowerShell could do this for you).

If you want to go for a coding solution then you could access your data maybe through web services.

Alternative option of course are creating a SharePoint Add-in or maybe even the new SPFx could be of some help.

Why do you want to use InfoPath? if users can ever be on a mobile device, their experience will not be very good.

You may want to take a look at PowerApps, you can set up a Data Gateway to provide access to on-prem data

Hi,
Using csv is simplest method but you need to create list columns with corresponding csv header name.then try below script, here i create simple script with two column and two csv header so you can change column name and header value in the script and this script based on pnp sharepoint online powershell module so you need to install pnp sharepoint online powershell module . 

$cred= Get-Credential
$Listname= "Listname"
Connect-PnPOnline -Url https://TenantName.sharepoint.com/sites/contosobeta -Credentials $cred
$csv = Import-Csv "C:\Users\csv\users2.csv" 
$ctx=Get-PnPContext
$list= Get-PnPList -Identity $Listname
foreach ($line in $csv)  
{  

$listItemInfo = New-Object Microsoft.SharePoint.Client.ListItemCreationInformation  
    $listItem = $list.AddItem($listItemInfo)  
    $listItem["Listcolumn1"] = $line.Csvheadername1 
    $listItem["Listcolumn2"] = $line.Csvheadername2 
    $listItem.Update()      
    $ctx.load($list)      
    $ctx.executeQuery()  
}

Note:

Before run the script youneed modify following value in the script

$Listname= "Listname"
$listItem["Listcolumn1"] = $line.Csvheadername1 
$listItem["Listcolumn2"] = $line.Csvheadername2