Pandasを使って、大文字小文字を区別しないWord Cloudを作成して下さい。
import pandas as pd
data = pd.DataFrame({'text' : ['This is a text', 'This is also a text', 'I love python'] })
import pandas as pd
from wordcloud import WordCloud
import matplotlib.pyplot as plt

# データの読み込み
data = pd.DataFrame({'text' : ['This is a text', 'This is also a text', 'I love python']})

# 単語出現数の計算
word_counts = data['text'].str.split(expand=True).stack().value_counts()

# WordCloudの作成 
wc = WordCloud(background_color = "white", collocations = False, normalize_plurals=True).generate_from_frequencies(word_counts)

# 作成したWordCloudを表示
plt.imshow(wc, interpolation='bilinear')
plt.axis("off")
plt.show()