diff --git a/command/issue.go b/command/issue.go
index d467986a1..305b6f832 100644
--- a/command/issue.go
+++ b/command/issue.go
@@ -391,11 +391,14 @@ func issueCreate(cmd *cobra.Command, args []string) error {
 		// TODO: move URL generation into GitHubRepository
 		openURL := fmt.Sprintf("https://github.com/%s/issues/new", ghrepo.FullName(baseRepo))
 		if title != "" || body != "" {
-			openURL += fmt.Sprintf(
-				"?title=%s&body=%s",
-				url.QueryEscape(title),
-				url.QueryEscape(body),
-			)
+			milestone := ""
+			if len(milestoneTitles) > 0 {
+				milestone = milestoneTitles[0]
+			}
+			openURL, err = withPrAndIssueQueryParams(openURL, title, body, assignees, labelNames, projectNames, milestone)
+			if err != nil {
+				return err
+			}
 		} else if len(templateFiles) > 1 {
 			openURL += "/choose"
 		}
@@ -450,12 +453,15 @@ func issueCreate(cmd *cobra.Command, args []string) error {
 	}
 
 	if action == PreviewAction {
-		openURL := fmt.Sprintf(
-			"https://github.com/%s/issues/new/?title=%s&body=%s",
-			ghrepo.FullName(baseRepo),
-			url.QueryEscape(title),
-			url.QueryEscape(body),
-		)
+		openURL := fmt.Sprintf("https://github.com/%s/issues/new/", ghrepo.FullName(baseRepo))
+		milestone := ""
+		if len(milestoneTitles) > 0 {
+			milestone = milestoneTitles[0]
+		}
+		openURL, err = withPrAndIssueQueryParams(openURL, title, body, assignees, labelNames, projectNames, milestone)
+		if err != nil {
+			return err
+		}
 		// TODO could exceed max url length for explorer
 		fmt.Fprintf(cmd.ErrOrStderr(), "Opening %s in your browser.\n", displayURL(openURL))
 		return utils.OpenInBrowser(openURL)
diff --git a/command/issue_test.go b/command/issue_test.go
index 0bb2707dc..a612cfab4 100644
--- a/command/issue_test.go
+++ b/command/issue_test.go
@@ -646,7 +646,7 @@ func TestIssueCreate_webTitleBody(t *testing.T) {
 		t.Fatal("expected a command to run")
 	}
 	url := strings.ReplaceAll(seenCmd.Args[len(seenCmd.Args)-1], "^", "")
-	eq(t, url, "https://github.com/OWNER/REPO/issues/new?title=mytitle&body=mybody")
+	eq(t, url, "https://github.com/OWNER/REPO/issues/new?body=mybody&title=mytitle")
 	eq(t, output.String(), "Opening github.com/OWNER/REPO/issues/new in your browser.\n")
 }
 
diff --git a/command/pr_create.go b/command/pr_create.go
index 96dc08791..45ec801d4 100644
--- a/command/pr_create.go
+++ b/command/pr_create.go
@@ -250,6 +250,9 @@ func prCreate(cmd *cobra.Command, _ []string) error {
 	if isDraft && isWeb {
 		return errors.New("the --draft flag is not supported with --web")
 	}
+	if len(reviewers) > 0 && isWeb {
+		return errors.New("the --reviewer flag is not supported with --web")
+	}
 
 	didForkRepo := false
 	// if a head repository could not be determined so far, automatically create
@@ -337,7 +340,14 @@ func prCreate(cmd *cobra.Command, _ []string) error {
 
 		fmt.Fprintln(cmd.OutOrStdout(), pr.URL)
 	} else if action == PreviewAction {
-		openURL := generateCompareURL(baseRepo, baseBranch, headBranchLabel, title, body)
+		milestone := ""
+		if len(milestoneTitles) > 0 {
+			milestone = milestoneTitles[0]
+		}
+		openURL, err := generateCompareURL(baseRepo, baseBranch, headBranchLabel, title, body, assignees, labelNames, projectNames, milestone)
+		if err != nil {
+			return err
+		}
 		// TODO could exceed max url length for explorer
 		fmt.Fprintf(cmd.ErrOrStderr(), "Opening %s in your browser.\n", displayURL(openURL))
 		return utils.OpenInBrowser(openURL)
@@ -389,20 +399,46 @@ func determineTrackingBranch(remotes context.Remotes, headBranch string) *git.Tr
 	return nil
 }
 
-func generateCompareURL(r ghrepo.Interface, base, head, title, body string) string {
+func withPrAndIssueQueryParams(baseURL, title, body string, assignees, labels, projects []string, milestone string) (string, error) {
+	u, err := url.Parse(baseURL)
+	if err != nil {
+		return "", nil
+	}
+	q := u.Query()
+	if title != "" {
+		q.Set("title", title)
+	}
+	if body != "" {
+		q.Set("body", body)
+	}
+	if len(assignees) > 0 {
+		q.Set("assignees", strings.Join(assignees, ","))
+	}
+	if len(labels) > 0 {
+		q.Set("labels", strings.Join(labels, ","))
+	}
+	if len(projects) > 0 {
+		q.Set("projects", strings.Join(projects, ","))
+	}
+	if milestone != "" {
+		q.Set("milestone", milestone)
+	}
+	u.RawQuery = q.Encode()
+	return u.String(), nil
+}
+
+func generateCompareURL(r ghrepo.Interface, base, head, title, body string, assignees, labels, projects []string, milestone string) (string, error) {
 	u := fmt.Sprintf(
 		"https://github.com/%s/compare/%s...%s?expand=1",
 		ghrepo.FullName(r),
 		base,
 		head,
 	)
-	if title != "" {
-		u += "&title=" + url.QueryEscape(title)
+	url, err := withPrAndIssueQueryParams(u, title, body, assignees, labels, projects, milestone)
+	if err != nil {
+		return "", err
 	}
-	if body != "" {
-		u += "&body=" + url.QueryEscape(body)
-	}
-	return u
+	return url, nil
 }
 
 var prCreateCmd = &cobra.Command{