How can I manage file attachments and association with records by using Current Document Link?

 In the context of Salesforce, here are the appropriate approaches given for your particular Objective:-

Creating Content Documents for the contract document

When a user uploads a contract document, a content document record is created for storing the file content in Salesforce.

Link content Document to account record

You can use the context Document link to associate the uploaded contract document with the appropriate account record.

Ensuring access control

You can set the share type and visibility Field in the content Document to control access to the linked content document.

Here is the example given of how you can Create a Content Document and link it to the account record by using the Content Document link in the Salesforce apex:-

Public class ContractDocumentManager {
    // Method to upload contract document and link it to Account record
    Public void uploadAndLinkContractDocument(Id accountId, String documentTitle, String documentContent) {
        // Create ContentVersion for contract document
        ContentVersion cv = new ContentVersion();
        cv.Title = documentTitle;
        cv.PathOnClient = ‘contract.pdf’;
        cv.VersionData = Blob.valueOf(documentContent);
        insert cv;
        // Link ContentVersion to Account record using ContentDocumentLink
        ContentDocumentLink cdl = new ContentDocumentLink();
        cdl.ContentDocumentId = cv.ContentDocumentId;
        cdl.LinkedEntityId = accountId;
        cdl.ShareType = ‘V’; // Viewer access
        cdl.Visibility = ‘AllUsers’; // All users within the Account
        insert cdl;
    }
}