diff --git a/src/mailgo.ts b/src/mailgo.ts
index 994d7d8..2f59c5e 100644
--- a/src/mailgo.ts
+++ b/src/mailgo.ts
@@ -123,7 +123,7 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     detailCc.id = "m-cc";
     let ccSpan = createElement(span);
     ccSpan.className = "w-500";
-    ccSpan.appendChild(createTextNode(strings.cc));
+    ccSpan.appendChild(createTextNode(strings.cc || defaultStrings.cc));
     ccValue = createElement(span);
     ccValue.id = "m-cc-value";
     detailCc.appendChild(ccSpan);
@@ -134,7 +134,7 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     detailBcc.id = "m-bcc";
     let bccSpan = createElement(span);
     bccSpan.className = "w-500";
-    bccSpan.appendChild(createTextNode(strings.bcc));
+    bccSpan.appendChild(createTextNode(strings.bcc || defaultStrings.bcc));
     bccValue = createElement(span);
     bccValue.id = "m-bcc-value";
     detailBcc.appendChild(bccSpan);
@@ -145,7 +145,9 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     detailSubject.id = "m-subject";
     let subjectSpan = createElement(span);
     subjectSpan.className = "w-500";
-    subjectSpan.appendChild(createTextNode(strings.subject));
+    subjectSpan.appendChild(
+      createTextNode(strings.subject || defaultStrings.subject)
+    );
     subjectValue = createElement(span);
     subjectValue.id = "m-subject-value";
     detailSubject.appendChild(subjectSpan);
@@ -156,7 +158,7 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     detailBody.id = "m-body";
     let bodySpan = createElement(span);
     bodySpan.className = "w-500";
-    bodySpan.appendChild(createTextNode(strings.body));
+    bodySpan.appendChild(createTextNode(strings.body || defaultStrings.body));
     bodyValue = createElement(span);
     bodyValue.id = "m-body-value";
     detailBody.appendChild(bodySpan);
@@ -171,7 +173,9 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     gmail.href = DEFAULT_BTN_HREF;
     gmail.classList.add("m-open");
     gmail.classList.add("m-gmail");
-    gmail.appendChild(createTextNode(strings.open_in));
+    gmail.appendChild(
+      createTextNode(strings.open_in || defaultStrings.open_in)
+    );
     let gmailSpan = createElement(span);
     gmailSpan.className = "w-500";
     gmailSpan.appendChild(createTextNode("Gmail"));
@@ -185,7 +189,9 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     outlook.href = DEFAULT_BTN_HREF;
     outlook.classList.add("m-open");
     outlook.classList.add("m-outlook");
-    outlook.appendChild(createTextNode(strings.open_in));
+    outlook.appendChild(
+      createTextNode(strings.open_in || defaultStrings.open_in)
+    );
     let outlookSpan = createElement(span);
     outlookSpan.className = "w-500";
     outlookSpan.appendChild(createTextNode("Outlook"));
@@ -259,7 +265,9 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     // by default not display
     telegram.style.display = "none";
 
-    telegram.appendChild(createTextNode(strings.open_in));
+    telegram.appendChild(
+      createTextNode(strings.open_in || defaultStrings.open_in)
+    );
     let telegramSpan = createElement(span);
     telegramSpan.className = "w-500";
     telegramSpan.appendChild(createTextNode("Telegram"));
@@ -273,7 +281,7 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     wa.href = DEFAULT_BTN_HREF;
     wa.classList.add("m-open");
     wa.classList.add("m-wa");
-    wa.appendChild(createTextNode(strings.open_in));
+    wa.appendChild(createTextNode(strings.open_in || defaultStrings.open_in));
     let waSpan = createElement(span);
     waSpan.className = "w-500";
     waSpan.appendChild(createTextNode("WhatsApp"));
@@ -287,7 +295,9 @@ const mailgoInit = (mailgoConfig?: MailgoConfig): void => {
     skype.href = DEFAULT_BTN_HREF;
     skype.classList.add("m-open");
     skype.classList.add("m-skype");
-    skype.appendChild(createTextNode(strings.open_in));
+    skype.appendChild(
+      createTextNode(strings.open_in || defaultStrings.open_in)
+    );
     let skypeSpan = createElement(span);
     skypeSpan.className = "w-500";
     skypeSpan.appendChild(createTextNode("Skype"));