public class testApex {
    public static void method(){
        try{
            //collecting contentdocumentlink record from contentdocumentlink 
            List<ContentDocumentLink> cdlList = [SELECT Id,ContentDocumentId, LinkedEntityId FROM ContentDocumentLink WHERE ContentDocumentId='0695j00000Hql43AAB'];
            system.debug('ContentDocumentLink Record:'+cdlList);
            
            //collecting linkedentityid to find object from contentdocumentlink
            List<Id> LinkedEntyId = new List<Id>();
            for (ContentDocumentlink cd1 :cdlList) {
                LinkedEntyId.add(cd1.LinkedEntityId);
            }
            system.debug('LinkedEntityId'+LinkedEntyId);
            
            //colleting those records where linkedentityid==contactid
            List<Contact>cList=[SELECT Id,LastName,Profile_Image__c,Description FROM Contact WHERE Id =:LinkedEntyId];
            system.debug('Contact list where attachment is added'+cList);
            List<Contact> updatedContacts = new List<Contact>();
            for (Contact contact : cList) {
                contact.Description = 'attachment inserted';
                updatedContacts.add(contact);
            }
            update updatedContacts;
            
        }
        catch(Exception e){
            system.debug('Error Message:'+e);
        }
    }
    
}